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Author  |
Mikhailova, D.; Karakulina, O.M.; Batuk, D.; Hadermann, J.; Abakumov, A.M.; Herklotz, M.; Tsirlin, A.A.; Oswald, S.; Giebeler, L.; Schmidt, M.; Eckert, J.; Knapp, M.; Ehrenberg, H. |
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Title |
Layered-to-Tunnel Structure Transformation and Oxygen Redox Chemistry in LiRhO2upon Li Extraction and Insertion |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Inorganic chemistry |
Abbreviated Journal |
Inorg Chem |
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Volume |
55 |
Issue |
55 |
Pages |
7079-7089 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Layered Li(M,Li)O2 (where M is a transition metal) ordered rock-salt-type structures are used in advanced metal-ion batteries as one of the best hosts for the reversible intercalation of Li ions. Besides the conventional redox reaction involving oxidation/reduction of the M cation upon Li extraction/insertion, creating oxygen-located holes because of the partial oxygen oxidation increases capacity while maintaining the oxidized oxygen species in the lattice through high covalency of the M–O bonding. Typical degradation mechanism of the Li(M,Li)O2 electrodes involves partially irreversible M cation migration toward the Li positions, resulting in gradual capacity/voltage fade. Here, using LiRhO2 as a model system (isostructural and isoelectronic to LiCoO2), for the first time, we demonstrate an intimate coupling between the oxygen redox and M cation migration. A formation of the oxidized oxygen species upon electrochemical Li extraction coincides with transformation of the layered Li1–xRhO2 structure into the γ-MnO2-type rutile–ramsdellite intergrowth LiyRh3O6 structure with rutile-like [1 × 1] channels along with bigger ramsdellite-like [2 × 1] tunnels through massive and concerted Rh migration toward the empty positions in the Li layers. The oxidized oxygen dimers with the O–O distances as short as 2.26 Å are stabilized in this structure via the local Rh–O configuration reminiscent to that in the μ-peroxo-μ-hydroxo Rh complexes. The LiyRh3O6 structure is remarkably stable upon electrochemical cycling illustrating that proper structural implementation of the oxidized oxygen species can open a pathway toward deliberate employment of the anion redox chemistry in high-capacity/high-voltage positive electrodes for metal-ion batteries. Upon chemical or electrochemical oxidation, layered LiRhO2 shows a unique structural transformation that involves both cation migration and oxidation of oxygen resulting in a stable tunnel-like rutile−ramsdellite intergrowth LiyRh3O6 structure. This structure demonstrates excellent performance with the steady and reversible capacity of ∼200 mAh/g. The stability of LiyRh3O6 is rooted in the accommodation of partially oxidized oxygen species through the formation of short O−O distances that are compatible with the connectivity of RhO6 octahedra. |
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Wos |
000380181400035 |
Publication Date |
2016-07-18 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0020-1669 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.857 |
Times cited |
12 |
Open Access |
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Notes |
Bundesministerium fur Bildung und Forschung, 03SF0477B ; Fonds Wetenschappelijk Onderzoek, G040116N ; |
Approved |
Most recent IF: 4.857 |
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Call Number |
EMAT @ emat @ c:irua:140848 |
Serial |
4424 |
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Author |
Mijin, S.D.; Baum, A.; Bekaert, J.; Solajic, A.; Pesic, J.; Liu, Y.; He, G.; Milošević, M.V.; Petrovic, C.; Popovic, Z., V; Hackl, R.; Lazarevic, N. |
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Title |
Probing charge density wave phases and the Mott transition in 1T-TaS₂I by inelastic light scattering |
Type |
A1 Journal article |
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Year |
2021 |
Publication |
Physical Review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
103 |
Issue |
24 |
Pages |
245133 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We present a polarization-resolved, high-resolution Raman scattering study of the three consecutive charge density wave (CDW) regimes in 1T-TaS2 single crystals, supported by ab initio calculations. Our analysis of the spectra within the low-temperature commensurate (C-CDW) regime shows P (3) over bar symmetry of the system, thus excluding the previously proposed triclinic stacking of the “star-of-David” structure, and promoting trigonal or hexagonal stacking instead. The spectra of the high-temperature incommensurate (IC-CDW) phase directly project the phonon density of states due to the breaking of the translational invariance, supplemented by sizable electron-phonon coupling. Between 200 and 352 K, our Raman spectra show contributions from both the IC-CDW and the C-CDW phases, indicating their coexistence in the so-called nearly commensurate (NC-CDW) phase. The temperature dependence of the symmetry-resolved Raman conductivity indicates the stepwise reduction of the density of states in the CDW phases, followed by a Mott transition within the C-CDW phase. We determine the size of the Mott gap to be Omega(gap) approximate to 170-190 meV, and track its temperature dependence. |
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Wos |
000664450500002 |
Publication Date |
2021-06-22 |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9969; 2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
4 |
Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 3.836 |
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Call Number |
UA @ admin @ c:irua:179664 |
Serial |
7015 |
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Author |
Mihucz, V.G.; Varga, Z.; Tatár, E.; Virág, I.; Van Grieken, R.; Koleszár, Z.; Záray, G. |
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Title |
Redistribution of uranium and thorium by soil/plant interaction in a recultivated mining area |
Type |
A1 Journal article |
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Year |
2008 |
Publication |
Microchemical journal |
Abbreviated Journal |
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Volume |
90 |
Issue |
1 |
Pages |
44-49 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
During the recultivation of the uranium mining area of Kõvágószõlõs (Hungary), the tailings were covered with clay and loess soil layers having a thickness of 30 cm and 100 cm, respectively. In the loess covering layer, acacia (Robinia pseudoacacia), poplars (Populus × albus, Populus × canescens), oak (Quercus pubescens), silver tree (Eleagnus angustifolia) were planted between 1996 and 2004. In order to establish the extent of the uranium and thorium transport from the sludge to the leaves by uptake and translocation processes through roots with a length higher than 1.3 m results in a remarkable redistribution of these pollutants, a gray poplar tree, growing spontaneously in the last uncovered tailing, being selected as reference tree. The U and Th concentrations in the leaves of the above-mentioned trees, in the covering layers as well as in the original sludge were determined by inductively coupled plasma sector field mass spectrometry (ICP-SF-MS). Generally, the Th concentration of the soils was about 4 times higher than that of uranium, while uranium concentration was about 10130 times higher than that of thorium in the leaf samples and its concentration ranged from 28 to 1045 ng g− 1, the last value belonging to the poplar tree growing on the last uncovered tailing. In order to assume the mobility and bioavailability of uranium if the dry leaves fall down, the uranium species in the leaves of the poplar tree growing in the uncovered reservoir were determined applying ultrasound-assisted extraction with distilled water and ammonium acetate as well as high performance liquid chromatographic (HPLC)-ICP-SF-MS technique. About 20% of total uranium could be extracted in form of uranyl cations and a presumably negatively charged uranium compound. Estimations revealed that the annual increment of U in the soil surface layer due to the dead fallen leaves in case of the investigated gray poplar (Populus × canescens) is about 1.2%. |
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Wos |
000258744000008 |
Publication Date |
2008-03-21 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0026-265x; 0026-265x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:70717 |
Serial |
8464 |
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Author |
Mihailescu, I.N.; Gyorgy, E.; Marin, G.; Popescu, M.; Teodorescu, V.S.; van Landuyt, J.; Grivas, C.; Hatziapostolou, A. |
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Title |
Crystalline structure of very hard tungsten carbide thin films obtained by reactive pulsed laser deposition |
Type |
A1 Journal article |
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Year |
1999 |
Publication |
Journal of vacuum science and technology: A: vacuum surfaces and films |
Abbreviated Journal |
J Vac Sci Technol A |
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Volume |
17 |
Issue |
1 |
Pages |
249-255 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
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Place of Publication |
New York, N.Y. |
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Language |
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Wos |
000078136300038 |
Publication Date |
2002-07-27 |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0734-2101; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
1.374 |
Times cited |
8 |
Open Access |
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Notes |
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Approved |
Most recent IF: 1.374; 1999 IF: 1.742 |
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Call Number |
UA @ lucian @ c:irua:29689 |
Serial |
581 |
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Author |
Miglio, A.; Saniz, R.; Waroquiers, D.; Stankovski, M.; Giantomassi, M.; Hautier, G.; Rignanese, G.-M.; Gonze, X. |
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Title |
Computed electronic and optical properties of SnO2 under compressive stress |
Type |
A1 Journal article |
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Year |
2014 |
Publication |
Optical materials |
Abbreviated Journal |
Opt Mater |
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Volume |
38 |
Issue |
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Pages |
161-166 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We consider the effects of three different types of applied compressive stress on the structural, electronic and optical properties of rutile SnO2. We use standard density functional theory (OFT) to determine the structural parameters. The effective masses and the electronic band gap, as well as their stress derivatives, are computed within both DFT and many-body perturbation theory (MBPT). The stress derivatives for the SnO2 direct band gap are determined to be 62, 38 and 25 meV/GPa within MBPT for applied hydrostatic, biaxial and uniaxial stress, respectively. Compared to DFT, this is a clear improvement with respect to available experimental data. We also estimate the exciton binding energies and their stress coefficients and compute the absorption spectrum by solving the Bethe-Salpeter equation. (C) 2014 Elsevier B.V. All rights reserved. |
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Corporate Author |
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Publisher |
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Place of Publication |
Amsterdam |
Editor |
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Language |
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Wos |
000346228800028 |
Publication Date |
2014-11-08 |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0925-3467; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.238 |
Times cited |
6 |
Open Access |
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Notes |
; This work was supported by the FRS-FNRS through a FRIA grant (D.W.) and a FNRS grant (G.H.). This work was also supported by the IWT Project Number 080023 (ISIMADE), the Region Wallonne through WALL-ETSF project Number 816849, the EU-FP7 HT4TCOS Grant No. PCIG11-GA-2912-321988, the FRS-FNRS through contracts FRFC Number 2.4.589.09.F and AIXPHO (PDR Grant T-0238.13). The authors would like to thank Yann Pouillon and Jean-Michel Beuken for their valuable technical support and help with the test and build system of ABINIT. Computational resources have been provided by the supercomputing facilities of the Universite catholique de Louvain (CISM/UCL) and the Consortium des Equipements de Calcul Intensif en Federation Wallonie Bruxelles (CECI) funded by the Fonds de la Recherche Scientifique de Belgique (FRS-FNRS) under Grant No. 2.5020.11. ; |
Approved |
Most recent IF: 2.238; 2014 IF: 1.981 |
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Call Number |
UA @ lucian @ c:irua:122747 |
Serial |
460 |
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Author |
Michotte, S.; Mátéfi-Tempfli, S.; Piraux, L.; Vodolazov, D.Y.; Peeters, F.M. |
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Title |
Condition for the occurrence of phase slip centers in superconducting nanowires under applied current or voltage |
Type |
A1 Journal article |
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Year |
2004 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
69 |
Issue |
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Pages |
094512,1-12 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
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Corporate Author |
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Place of Publication |
Lancaster, Pa |
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Wos |
000220812800111 |
Publication Date |
2004-03-18 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
61 |
Open Access |
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Notes |
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Approved |
Most recent IF: 3.836; 2004 IF: 3.075 |
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Call Number |
UA @ lucian @ c:irua:69383 |
Serial |
475 |
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Author |
Michielsen, I.; Uytdenhouwen, Y.; Pype, J.; Michielsen, B.; Mertens, J.; Reniers, F.; Meynen, V.; Bogaerts, A. |
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Title |
CO 2 dissociation in a packed bed DBD reactor: First steps towards a better understanding of plasma catalysis |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Chemical engineering journal |
Abbreviated Journal |
Chem Eng J |
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Volume |
326 |
Issue |
326 |
Pages |
477-488 |
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Keywords |
A1 Journal article; Laboratory of adsorption and catalysis (LADCA); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
Plasma catalysis is gaining increasing interest for CO2 conversion, but the interaction between the plasma and catalyst is still poorly understood. This is caused by limited systematic materials research, since most works combine a plasma with commercial supported catalysts and packings. In the present paper, we study the influence of specific material and reactor properties, as well as reactor/bead configuration, on the conversion and energy efficiency of CO2 dissociation in a packed bed dielectric barrier discharge (DBD) reactor. Of the various packing materials investigated, BaTiO3 yields the highest conversion and energy efficiency, i.e., 25% and 4.5%.
Our results show that, when evaluating the influence of catalysts, the impact of the packing (support) material itself cannot be neglected, since it can largely affect the conversion and energy efficiency. This shows the large potential for further improvement of packed bed plasma reactors for CO2 conversion and other chemical conversion reactions by adjusting both packing (support) properties and catalytically active sites. Moreover, we clearly prove that comparison of results obtained in different reactor setups should be done with care, since there is a large effect of the reactor setup and reactor/bead configuration. |
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Corporate Author |
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Place of Publication |
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Wos |
000406137200047 |
Publication Date |
2017-06-01 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1385-8947 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.216 |
Times cited |
49 |
Open Access |
OpenAccess |
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Notes |
This research was carried out with financial support of the Institute for the Promotion of Innovation by Science and Technology in Flanders (IWT Flanders) for both I. Michielsen (IWT-141093) and J. Pype (IWT-131229) and of the Walloon region through the excellence programme FLYCOAT (nr. 1318147) for the profilometry measurements. The authors also acknowledge financial support from an IOF-SBO project from the University of Antwerp and from the Fund for Scientific Research (FWO; grant number: G.0254.14 N). This research was carried out in the framework of the network on Physical Chemistry of Plasma-Surface Interactions – Interuniversity Attraction Poles, phase VII (http://psi-iap7.ulb. ac.be/), and supported by the Belgian Science Policy Office (BELSPO). The authors would also like to thank Koen Van Laer for the discussions on this manuscript. |
Approved |
Most recent IF: 6.216 |
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Call Number |
PLASMANT @ plasmant @ c:irua:144802 |
Serial |
4626 |
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Author |
Michielsen, I.; Uytdenhouwen, Y.; Bogaerts, A.; Meynen, V. |
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Title |
Altering conversion and product selectivity of dry reforming of methane in a dielectric barrier discharge by changing the dielectric packing material |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Catalysts |
Abbreviated Journal |
Catalysts |
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Volume |
9 |
Issue |
1 |
Pages |
51 |
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Keywords |
A1 Journal article; Laboratory of adsorption and catalysis (LADCA); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
We studied the influence of dense, spherical packing materials, with different chemical compositions, on the dry reforming of methane (DRM) in a dielectric barrier discharge (DBD) reactor. Although not catalytically activated, a vast effect on the conversion and product selectivity could already be observed, an influence which is often neglected when catalytically activated plasma packing materials are being studied. The alpha-Al2O3 packing material of 2.0-2.24 mm size yields the highest total conversion (28%), as well as CO2 (23%) and CH4 (33%) conversion and a high product fraction towards CO (similar to 70%) and ethane (similar to 14%), together with an enhanced CO/H-2 ratio of 9 in a 4.5 mm gap DBD at 60 W and 23 kHz. gamma-Al2O3 is only slightly less active in total conversion (22%) but is even more selective in products formed than alpha-Al2O3 BaTiO3 produces substantially more oxygenated products than the other packing materials but is the least selective in product fractions and has a clear negative impact on CO2 conversion upon addition of CH4. Interestingly, when comparing to pure CO2 splitting and when evaluating differences in products formed, significantly different trends are obtained for the packing materials, indicating a complex impact of the presence of CH4 and the specific nature of the packing materials on the DRM process. |
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Corporate Author |
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Wos |
000459732000051 |
Publication Date |
2019-01-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2073-4344 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles; WoS full record; WoS citing articles |
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Impact Factor |
3.082 |
Times cited |
4 |
Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 3.082 |
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Call Number |
UA @ admin @ c:irua:158666 |
Serial |
5268 |
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Author |
Michielsen, B.; Verlackt, C.; van der Veken, B.J.; Herrebout, W.A. |
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Title |
C-H\cdots X (X = S, P) hydrogen bonding : the complexes of halothane with dimethyl sulfide and trimethylphosphine |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Journal Of Molecular Structure |
Abbreviated Journal |
J Mol Struct |
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Volume |
1023 |
Issue |
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Pages |
90-95 |
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Keywords |
A1 Journal article; Electron Microscopy for Materials Science (EMAT); |
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Abstract |
The formation of CH⋯S and CH⋯P hydrogen bonded complexes of halothane, CHBrClCF3, with dimethyl sulfide(-d6) and trimethylphosphine(-d9) have been studied in solutions of liquid krypton using infrared and Raman spectroscopy. In the 1:1 complexes, the halothane CH stretching mode is found to be red-shifted by 43 cm−1 in the dimethyl sulfide complex, and by 63 cm−1 in the trimethylphosphine complex. The complexation enthalpies were derived and amount to −10.7(2) and −11.2(2) kJ mol−1 for the respective complexes. The experiments were supported by ab initio calculations and Monte Carlo simulations. The obtained data for the CH⋯S and CH⋯P hydrogen bonds is compared to that of corresponding CH⋯O and CH⋯N hydrogen bonds. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Amsterdam |
Editor |
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Language |
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Wos |
000308971900017 |
Publication Date |
2012-03-23 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0022-2860; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
1.753 |
Times cited |
21 |
Open Access |
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Notes |
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Approved |
Most recent IF: 1.753; 2012 IF: 1.404 |
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Call Number |
UA @ lucian @ c:irua:100917 |
Serial |
3519 |
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Author |
Michiels, R.; Engelmann, Y.; Bogaerts, A. |
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Title |
Plasma Catalysis for CO2Hydrogenation: Unlocking New Pathways toward CH3OH |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Journal Of Physical Chemistry C |
Abbreviated Journal |
J Phys Chem C |
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Volume |
124 |
Issue |
47 |
Pages |
25859-25872 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Movement Antwerp (MOVANT) |
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Abstract |
We developed a microkinetic model to reveal the effects of plasma-generated radicals, intermediates, and vibrationally excited species on the catalytic hydrogenation of CO2 to CH3OH on a Cu(111) surface. As a benchmark, we first present the mechanisms of thermal catalytic CH3OH formation. Our model predicts that the reverse water-gas shift reaction followed by CO hydrogenation, together with the formate path, mainly contribute to CH3OH formation in thermal catalysis. Adding plasma-generated radicals and intermediates results in a higher CH3OH turnover frequency (TOF) by six to seven orders of magnitude, showing the potential of plasma-catalytic CO2 hydrogenation into CH3OH, in accordance with the literature. In addition, CO2 vibrational excitation further increases the CH3OH TOF, but the effect is limited due to relatively low vibrational temperatures under typical plasma catalysis conditions. The predicted increase in CH3OH formation by plasma catalysis is mainly attributed to the increased importance of the formate path. In addition, the conversion of plasma-generated CO to HCO* and subsequent HCOO* or H2CO* formation contribute to CH3OH formation. Both pathways bypass the HCOO* formation from CO2, which is the main bottleneck in the process. Hence, our model points toward the important role of CO, but also O, OH, and H radicals, as they influence the reactions that consume CO2 and CO. In addition, our model reveals that the H pressure should not be smaller than ca. half of the O pressure in the plasma as this would cause O* poisoning, which would result in very small product TOFs. Thus, plasma conditions should be targeted with a high CO and H content as this is favorable for CH3OH formation, while the O content should be minimized. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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| |
Language |
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Wos |
000595545800023 |
Publication Date |
2020-11-25 |
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Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1932-7447 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.7 |
Times cited |
|
Open Access |
Not_Open_Access: Available from 15.07.2021 |
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| |
Notes |
Universiteit Antwerpen; Fonds Wetenschappelijk Onderzoek, 1114921N ; H2020 European Research Council, 810182 ; We acknowledge the financial support from the Fund for Scientific Research (FWO-Vlaanderen; grant ID 1114921N) and from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 810182 − SCOPE ERC Synergy project) as well as from the DOC-PRO3 and the TOPBOF projects of the University of Antwerp. |
Approved |
Most recent IF: 3.7; 2020 IF: 4.536 |
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| |
Call Number |
PLASMANT @ plasmant @c:irua:173864 |
Serial |
6443 |
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| Permanent link to this record |
| |
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| |
|
Author |
Michel, K.H.; Verberck, B.; Nikolaev, A.V. |
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| |
Title |
Anisotropic packing and one-dimensional fluctuations of C60 molecules in carbon nanotubes |
Type |
A1 Journal article |
| |
Year |
2005 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
|
| |
Volume |
95 |
Issue |
18 |
Pages |
185506-185506,4 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The confinement of a C-60 molecule encapsulated in a cylindrical nanotube depends on the tube radius. In small tubes with radius R-T less than or similar to 7 A, a fivefold axis of the molecule coincides with the tube axis. The interaction between C-60 molecules in the nanotube is then described by a O-2-rotor model on a 1D liquid chain with coupling between orientational and displacive correlations. This coupling leads to chain contraction. The structure factor of the 1D liquid is derived. In tubes with a larger radius the molecular centers of mass are displaced off the tube axis. The distinction of two groups of peapods with on- and off-axis molecules suggests an explanation of the apparent splitting of A(g) modes of C-60 in nanotubes measured by resonant Raman scattering. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
New York, N.Y. |
Editor |
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| |
Language |
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Wos |
000232887400041 |
Publication Date |
2005-10-28 |
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| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0031-9007;1079-7114; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
8.462 |
Times cited |
40 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 8.462; 2005 IF: 7.489 |
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| |
Call Number |
UA @ lucian @ c:irua:94717 |
Serial |
127 |
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| Permanent link to this record |
| |
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| |
|
Author |
Michel, K.H.; Verberck, B.; Nikolaev, A.V. |
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| |
Title |
Nanotube field and one-dimensional fluctuations of C60 molecules in carbon nanotubes |
Type |
A1 Journal article |
| |
Year |
2005 |
Publication |
European physical journal : B : condensed matter and complex systems |
Abbreviated Journal |
Eur Phys J B |
|
| |
Volume |
48 |
Issue |
1 |
Pages |
113-124 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
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| |
Address |
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Corporate Author |
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Thesis |
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| |
Publisher |
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Place of Publication |
Berlin |
Editor |
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| |
Language |
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Wos |
000233998600016 |
Publication Date |
2005-12-13 |
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| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1434-6028;1434-6036; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
1.461 |
Times cited |
25 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 1.461; 2005 IF: 1.720 |
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| |
Call Number |
UA @ lucian @ c:irua:56408 |
Serial |
2279 |
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| Permanent link to this record |
| |
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| |
|
Author |
Michel, K.H.; Verberck, B.; Nikolaev, A. |
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| |
Title |
Mercator maps of orientations of a C60 molecule in single-walled nanotubes with distinct radii |
Type |
A1 Journal article |
| |
Year |
2005 |
Publication |
AIP conference proceedings |
Abbreviated Journal |
|
|
| |
Volume |
786 |
Issue |
|
Pages |
69-72 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
We study the confinement of a C-60 molecule encapsulated in a cylindrical nanotube as a function of the tube radius. Drawing the Mercator maps of the potential, we find two distinct molecular orientations; for tubes with small radii, R-T less than or similar to 7 angstrom, a fivefold axis of the molecule coincides with the tube long axis, for larger radii, R-T less than or similar to 8 angstrom, a threefold axis of the molecule coincides with the tube long axis. These different orientations are caused by the relative importance of the repulsive and the attractive parts of the van der Waals potentials of the molecule with the tube wall for small and large tubes respectively. Experimental evidence is provided by the apparent splitting of A(g) modes of the C-60 molecule in resonant Raman scattering. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
Amer inst physics |
Place of Publication |
Melville |
Editor |
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| |
Language |
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Wos |
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Publication Date |
0000-00-00 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
0094-243x |
ISBN |
|
Additional Links |
UA library record; WoS full record; |
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| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: NA |
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| |
Call Number |
UA @ lucian @ c:irua:94738 |
Serial |
1993 |
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| Permanent link to this record |
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| |
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Author |
Michel, K.H.; Verberck, B.; Hulman, M.; Kuzmany, H.; Krause, M. |
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| |
Title |
Superposition of quantum and classical rotational motions in Sc2C2@C84 fullerite |
Type |
A1 Journal article |
| |
Year |
2007 |
Publication |
The journal of chemical physics |
Abbreviated Journal |
J Chem Phys |
|
| |
Volume |
126 |
Issue |
6 |
Pages |
064304,1-15 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
New York, N.Y. |
Editor |
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| |
Language |
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Wos |
000244250200008 |
Publication Date |
2007-02-09 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0021-9606; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
2.965 |
Times cited |
14 |
Open Access |
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| |
Notes |
|
Approved |
Most recent IF: 2.965; 2007 IF: 3.044 |
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| |
Call Number |
UA @ lucian @ c:irua:63628 |
Serial |
3381 |
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| Permanent link to this record |
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Author |
Michel, K.H.; Verberck, B. |
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| |
Title |
Phonon dispersions and piezoelectricity in bulk and multilayers of hexagonal boron nitride |
Type |
A1 Journal article |
| |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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| |
Volume |
83 |
Issue |
11 |
Pages |
115328-115328,14 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
A unified theory of phonon dispersions and piezoelectricity in bulk and multilayers of hexagonal boron nitride (h-BN) is derived. The dynamical matrix is calculated on the basis of an empirical force constant model of intralayer valence and interlayer van der Waals interactions. Coulomb interactions are calculated by Ewalds method, adapted for the three-dimensional (3D) and the multilayer case. The deformation of the ionic charge distribution with long-wave lattice displacements is taken into account. Special attention is devoted to the nonanalytic long-range Coulomb contribution to the dynamical matrix which is different for the 3D crystal and the multilayer case. Consequently there is a splitting of the transverse optical (TO) and longitudinal optical (LO) phonon branches of E1u symmetry and a discontinuity of the A2u branch at the Γ point in 3D h-BN. No such splitting and discontinuity at Γ are present in multilayer crystals with a finite number N of layers. There a diverging bundle of N overbending optical phonon branches emerges from Γ. Borns long-wave theory is applied and extended for the study of piezoelectricity in layered crystals. While 3D h-BN and h-BN multilayers with an even number of layers (symmetry D6h) are not piezoelectric, multilayers with an uneven number of Nu layers (symmetry D3h) are piezoelectric; the piezoelectric coefficient e1,11 is inversely proportional to Nu. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000288783700005 |
Publication Date |
2011-03-24 |
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Series Editor |
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Series Title |
|
Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
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| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
82 |
Open Access |
|
|
| |
Notes |
; Discussions with G. Heger, B. Partoens, and F. M. Peeters are gratefully acknowledged. This work has been supported by the Flemish Science Foundation (FWO-V1) and the Bijzonder Onderzoeksfonds, Universiteit Antwerpen (BOF-UA). ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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| |
Call Number |
UA @ lucian @ c:irua:89602 |
Serial |
2603 |
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| Permanent link to this record |
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| |
|
Author |
Michel, K.H.; Verberck, B. |
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| |
Title |
Rigid-plane phonons in layered crystals |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physica status solidi: B: basic research |
Abbreviated Journal |
Phys Status Solidi B |
|
| |
Volume |
249 |
Issue |
12 |
Pages |
2604-2607 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
The determination of the layer number ${\cal N}$ in nanoscale thin layered crystals is a challenging problem of technological relevance. In addition to innovative experimental techniques, a thorough knowledge of the underlying lattice dynamics is required. Starting from phenomenological atomic interaction potentials we have carried out an analytical study of the low-frequency optical phonon dispersions in layered crystals. At the gamma point of the two-dimensional Brillouin zone the optical phonon frequencies correspond to rigid-plane shearing and compression modes. We have investigated graphene multilayers (GML) and hexagonal boron-nitride multilayers (BNML). The frequencies show a characteristic dependence on ${\cal N}$. The results which are represented in the form of fan diagrams are very similar for both materials. Due to charge neutrality within layers Coulomb forces play no role, only van der Waals forces between nearest neighbor layers are relevant. The theoretical results agree with recent low-frequency Raman results on rigid-layer modes [Tan et al., Nature Mater. 11, 294 (2012)] in GML and double-resonant Raman scattering data on rigid-layer compression modes [Herziger et al., Phys. Rev. B 85, 235447 (2012)] in GML. (C) 2012 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Berlin |
Editor |
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Language |
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Wos |
000312215300072 |
Publication Date |
2012-11-19 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
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Edition |
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| |
ISSN |
0370-1972; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
1.674 |
Times cited |
1 |
Open Access |
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Notes |
; This work has been supported by the Flemish Science Foundation (FWO-Vl) and the Bijzonder Onderzoeksfonds, Universiteit Antwerpen (BOF-UA). ; |
Approved |
Most recent IF: 1.674; 2012 IF: 1.489 |
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| |
Call Number |
UA @ lucian @ c:irua:105992 |
Serial |
2907 |
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| Permanent link to this record |
| |
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| |
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Author |
Michel, K.H.; Verberck, B. |
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| |
Title |
Theoretical phonon dispersions in monolayers and multilayers of hexagonal boron-nitride |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Physica status solidi: B: basic research |
Abbreviated Journal |
Phys Status Solidi B |
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| |
Volume |
246 |
Issue |
11/12 |
Pages |
2802-2805 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
Starting from an empirical force constant model of valence interactions and calculating by Ewald's method the electrostatic force constants, we derive the dynamical matrix for a monolayer and for multilayer systems of hexagonal boron nitride (h-BN). Solution of the secular problem leads to the corresponding phonon dispersion relations. The interplay between valence forces and Coulomb forces is discussed. A comparison with previous results on graphene and graphene multilayers is made. Our spectra on the h-BN monolayer are rather similar to previous ab initio theory results. Comparison is also made with Raman and infrared experimental results. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
Berlin |
Editor |
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Language |
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Wos |
000272904100091 |
Publication Date |
2009-11-12 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
0370-1972; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
1.674 |
Times cited |
10 |
Open Access |
|
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| |
Notes |
|
Approved |
Most recent IF: 1.674; 2009 IF: 1.150 |
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| |
Call Number |
UA @ lucian @ c:irua:80673 |
Serial |
3609 |
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| Permanent link to this record |
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Author |
Michel, K.H.; Verberck, B. |
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Title |
Theory of elastic and piezoelectric effects in two-dimensional hexagonal boron nitride |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
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| |
Volume |
80 |
Issue |
22 |
Pages |
224301,1-224301,10 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
Starting from an empirical force constant model of valence interactions and calculating by Ewalds method the ion-ion force constants, we derive the dynamical matrix for a monolayer crystal of hexagonal boron nitride (h-BN). The phonon dispersion relations are calculated. The interplay between valence and Coulomb forces is discussed. It is shown by analytical methods that the longitudinal and the transverse optical (LO and TO) phonon branches for in-plane motion are degenerate at the Γ point of the Brillouin zone. Away from Γ, the LO branch exhibits pronounced overbending. It is found that the nonanalytic Coulomb contribution to the dynamical matrix causes a linear increase of the LO branch with increasing wave vector starting at Γ. This effect is general for two-dimensional (2D) ionic crystals. Performing a long-wavelength expansion of the dynamical matrix, we use Borns perturbation method to calculate the elastic constants (tension coefficients). Since the crystal is noncentrosymmetric, internal displacements due to relative shifts between the two sublattices (B and N) contribute to the elastic constants. These internal displacements are responsible for piezoelectric and dielectric phenomena. The piezoelectric stress constant and the dielectric susceptibility of 2D h-BN are calculated. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000273228500045 |
Publication Date |
2009-12-21 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
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| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
96 |
Open Access |
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| |
Notes |
|
Approved |
Most recent IF: 3.836; 2009 IF: 3.475 |
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| |
Call Number |
UA @ lucian @ c:irua:80576 |
Serial |
3616 |
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| Permanent link to this record |
| |
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| |
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Author |
Michel, K.H.; Verberck, B. |
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| |
Title |
Theory of phonon dispersions and piezoelectricity in multilayers of hexagonal boron-nitride |
Type |
A1 Journal article |
| |
Year |
2011 |
Publication |
Physica status solidi: B: basic research |
Abbreviated Journal |
Phys Status Solidi B |
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| |
Volume |
248 |
Issue |
11 |
Pages |
2720-2723 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
Taking into account covalent, Coulomb and van der Waals interactions, we construct the dynamical matrix and calculate the phonon dispersion relations for multilayer crystals of hexagonal boron-nitride. Coulomb interactions account for a strong overbending of optical phonons. Applying and extending Born's long-wave theory to the case of multilayer crystals, we calculate the piezoelectric stress constant equation image as a function of the number of layers equation image. In agreement with group theory, we find that equation image for equation image even; for an uneven number equation image of layers we obtain equation image, i.e. the piezoelectric constant decreases as equation image. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
Berlin |
Editor |
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| |
Language |
|
Wos |
000297517100069 |
Publication Date |
2011-10-18 |
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| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
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| |
ISSN |
0370-1972; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
1.674 |
Times cited |
13 |
Open Access |
|
|
| |
Notes |
; Discussions with G. Heger, B. Partoens and F. M. Peeters are gratefully acknowledged. This work has been supported by the Flemish Science Foundation (FWO-Vl) and the Bijzonder Onderzoeksfonds, Universiteit Antwerpen (BOF-UA). ; |
Approved |
Most recent IF: 1.674; 2011 IF: 1.316 |
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| |
Call Number |
UA @ lucian @ c:irua:94034 |
Serial |
3618 |
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| Permanent link to this record |
| |
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| |
|
Author |
Michel, K.H.; Verberck, B. |
|
| |
Title |
Theory of rigid-plane phonon modes in layered crystals |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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| |
Volume |
85 |
Issue |
9 |
Pages |
094303-094303,11 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The lattice dynamics of low-frequency rigid-plane modes in metallic (graphene multilayers, GML) and in insulating (hexagonal boron-nitride multilayers, BNML) layered crystals is investigated. The frequencies of shearing and compression (stretching) modes depend on the layer number N and are presented in the form of fan diagrams. The results for GML and BNML are very similar. In both cases, only the interactions (van der Waals and Coulomb) between nearest-neighbor planes are effective, while the interactions between more distant planes are screened. A comparison with recent Raman scattering results on low-frequency shear modes in GML [Tan et al., Nat. Mater., in press, doi: 10.1038/nmat3245, (2012)] is made. Relations with the low-lying rigid-plane phonon dispersions in the bulk materials are established. Master curves, which connect the fan diagram frequencies for any given N, are derived. Static and dynamic thermal correlation functions for rigid-layer shear and compression modes are calculated. The results might be of use for the interpretation of friction force experiments on multilayer crystals. |
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Address |
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Corporate Author |
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Thesis |
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| |
Publisher |
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Place of Publication |
|
Editor |
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| |
Language |
|
Wos |
000301646000006 |
Publication Date |
2012-03-19 |
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| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
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| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
38 |
Open Access |
|
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| |
Notes |
; The authors are indebted to J. Maultzsch for bringing Ref. 20 to their attention. They thank D. Lamoen, F.M. Peeters, B. Trauzettel, and C. Van Haesendonck for useful discussions. This work has been financially supported by the Research Foundation Flanders (FWO). ; |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
|
| |
Call Number |
UA @ lucian @ c:irua:97787 |
Serial |
3619 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Michel, K.H.; Verberck, B. |
|
| |
Title |
Theory of the elastic constants of graphite and graphene |
Type |
A1 Journal article |
| |
Year |
2008 |
Publication |
Physica status solidi: B: basic research |
Abbreviated Journal |
Phys Status Solidi B |
|
| |
Volume |
245 |
Issue |
10 |
Pages |
2177-2180 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Born's long wave method is used to study the elastic properties of graphite and graphene. Starting from an empirical force constant model derived from full inplane phonon dispersions of graphite [Mohr et al., Phys. Rev. B 76, 035439 (2007)] we calculate the tension coefficients of graphene. Extending the model by interplanar interactions, we calculate the elastic constants of graphite. The agreement of our theoretical values with inelastic x-ray scattering results on elastic constants of graphite [Bosak et al., Phys. Rev. B 75, 153408 (2007)] is very satisfactory. |
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| |
Address |
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Corporate Author |
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Thesis |
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| |
Publisher |
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Place of Publication |
Berlin |
Editor |
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| |
Language |
|
Wos |
000260581800066 |
Publication Date |
2008-08-25 |
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| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0370-1972; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
1.674 |
Times cited |
47 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 1.674; 2008 IF: 1.166 |
|
| |
Call Number |
UA @ lucian @ c:irua:75660 |
Serial |
3621 |
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| Permanent link to this record |
| |
|
| |
|
Author |
Michel, K.H.; Verberck, B. |
|
| |
Title |
Theory of the evolution of phonon spectra and elastic constants from graphene to graphite |
Type |
A1 Journal article |
| |
Year |
2008 |
Publication |
Physical review : B : solid state |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
78 |
Issue |
8 |
Pages |
085424,1-085424,17 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
We present a unified theory of the phonon dispersions and elastic properties of graphene, graphite, and graphene multilayer systems. Starting from a fifth-nearest-neighbor force-constant model derived from full in-plane phonon dispersions of graphite [Mohr et al., Phys. Rev. B 76, 035439 (2007)], we use Born's long-wave method to calculate the tension and bending coefficients of graphene. Extending the model by interplanar interactions, we study the phonon dispersions and the elastic constants of graphite, and the phonon spectra of graphene multilayers. We find that the inner displacement terms due to sublattice shifts between inequivalent C atoms are quantitatively important in determining the elastomechanical properties of graphene and of graphite. The overall agreement between theory and experiment is very satisfactory. We investigate the evolution from graphene to graphite by studying the increase in the rigid plane optical mode as a function of the number of layers N. At N=10 the graphite value B2g1127 cm−1 is attained within a few percent. |
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| |
Address |
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Corporate Author |
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Thesis |
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| |
Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
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| |
Language |
|
Wos |
000259406900106 |
Publication Date |
2008-08-21 |
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| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
72 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 3.836; 2008 IF: 3.322 |
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| |
Call Number |
UA @ lucian @ c:irua:76527 |
Serial |
3622 |
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| Permanent link to this record |
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| |
|
Author |
Michel, K.H.; Scuracchio, P.; Peeters, F.M. |
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| |
Title |
Sound waves and flexural mode dynamics in two-dimensional crystals |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
96 |
Issue |
9 |
Pages |
094302 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Starting from a Hamiltonian with anharmonic coupling between in-plane acoustic displacements and outof-plane (flexural) modes, we derived coupled equations of motion for in-plane displacements correlations and flexural mode density fluctuations. Linear response theory and time-dependent thermal Green's functions techniques are applied in order to obtain different response functions. As external perturbations we allow for stresses and thermal heat sources. The displacement correlations are described by a Dyson equation where the flexural density distribution enters as an additional perturbation. The flexural density distribution satisfies a kinetic equation where the in-plane lattice displacements act as a perturbation. In the hydrodynamic limit this system of coupled equations is at the basis of a unified description of elastic and thermal phenomena, such as isothermal versus adiabatic sound motion and thermal conductivity versus second sound. The general theory is formulated in view of application to graphene, two-dimensional h-BN, and 2H-transition metal dichalcogenides and oxides. |
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Address |
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Corporate Author |
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Thesis |
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| |
Publisher |
American Physical Society |
Place of Publication |
New York, N.Y |
Editor |
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| |
Language |
|
Wos |
000409246200003 |
Publication Date |
2017-09-05 |
|
| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2469-9969; 2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
6 |
Open Access |
|
|
| |
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem program. ; |
Approved |
Most recent IF: 3.836 |
|
| |
Call Number |
UA @ lucian @ c:irua:145630 |
Serial |
4751 |
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| Permanent link to this record |
| |
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| |
|
Author |
Michel, K.H.; Nikolaev, A.V. |
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| |
Title |
Theory of distinct crystal structures of polymerized fullerides AC60, A=K, Rb, Cs: the specific role of alkalis |
Type |
A1 Journal article |
| |
Year |
2000 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
|
| |
Volume |
85 |
Issue |
|
Pages |
3197-3200 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
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| |
Address |
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Corporate Author |
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Thesis |
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| |
Publisher |
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Place of Publication |
New York, N.Y. |
Editor |
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| |
Language |
|
Wos |
000089807800033 |
Publication Date |
2002-07-27 |
|
| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0031-9007;1079-7114; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
8.462 |
Times cited |
16 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 8.462; 2000 IF: 6.462 |
|
| |
Call Number |
UA @ lucian @ c:irua:34339 |
Serial |
3615 |
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| Permanent link to this record |
| |
|
| |
|
Author |
Michel, K.H.; Neek-Amal, M.; Peeters, F.M. |
|
| |
Title |
Static flexural modes and piezoelectricity in 2D and layered crystals |
Type |
A1 Journal article |
| |
Year |
2016 |
Publication |
Physica status solidi: B: basic research |
Abbreviated Journal |
Phys Status Solidi B |
|
| |
Volume |
253 |
Issue |
253 |
Pages |
2311-2315 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
Piezo- and flexoelectricity are manifestations of electromechanical coupling in solids with potential applications in nanoscale materials. Naumov etal. [Phys. Rev. Lett. 102, 217601 (2009)] have shown by first principles calculations that a monolayer BN sheet becomes macroscopically polarized in-plane when in a corrugated state. Here, we investigate the interplay of layer corrugation and in-plane polarization by atomistic lattice dynamics. We treat the coupling between static flexural modes and in-plane atomic ion displacements as an anharmonic effect, similar to the membrane effect that is at the origin of negative thermal expansion in layered crystals. We have derived analytical expressions for the corrugation-induced static in-plane strains and the optical displacements with the resulting polarization response functions. Beyond h-BN, the theory applies to transition metal dichalcogenides and dioxides. Numerical calculations show that the effects are considerably stronger for 2D h-BN than for 2H-MoS2. |
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| |
Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
Berlin |
Editor |
|
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| |
Language |
|
Wos |
000390339000002 |
Publication Date |
2016-10-21 |
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| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0370-1972 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
1.674 |
Times cited |
5 |
Open Access |
|
|
| |
Notes |
; The authors acknowledge useful discussions with L. Wirtz, A. Molina-Sanchez, and C. Sevik. This work was supported by the ESF-Eurographene project CONGRAN, and the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 1.674 |
|
| |
Call Number |
UA @ lucian @ c:irua:140309 |
Serial |
4462 |
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| Permanent link to this record |
| |
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| |
|
Author |
Michel, K.H.; Lamoen, D.; David, W.I.F. |
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| |
Title |
Orientational order and disorder in solid C60 : theory and diffraction experiments |
Type |
A1 Journal article |
| |
Year |
1995 |
Publication |
Acta crystallographica: section A: foundations of crystallography |
Abbreviated Journal |
Acta Crystallogr A |
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| |
Volume |
51 |
Issue |
3 |
Pages |
365-374 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
Starting from a microscope model of the intermolecular potential, a unified description is presented of the Bragg scattering law in the orientationally disordered and in the ordered phase of solid C-60. The orientational structure factor is expanded in terms of symmetry-adapted surface harmonics. The expansion coefficients are calculated from theory and compared with experiment Their temperature evolution is studied in the disordered phase at the 260 K transitions and in the ordered phase. In the ordered phase, new results from high-resolution neutron powder diffraction are given. In the disordered phase, space group Fm $($) over bar$$ 3m, the reflections have A(1g) symmetry; in the ordered phase, space group Pa $$($) over bar 3, reflections of T-2g symmetry appear and in addition the A(1g) reflections are renormalized. The orientational density distribution is calculated. The effective crystal-field potential is constructed, its temperature evolution in the ordered phase is studied and related to the occurrence of an orientational glass. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Copenhagen |
Editor |
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Language |
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Wos |
A1995RB59400018 |
Publication Date |
2002-07-27 |
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| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0108-7673; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.307 |
Times cited |
14 |
Open Access |
|
|
| |
Notes |
|
Approved |
CHEMISTRY, MULTIDISCIPLINARY 65/163 Q2 # CRYSTALLOGRAPHY 10/26 Q2 # |
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| |
Call Number |
UA @ lucian @ c:irua:12189 |
Serial |
2518 |
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| Permanent link to this record |
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| |
|
Author |
Michel, K.H.; Costamagna; Peeters, F.M. |
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| |
Title |
Theory of anharmonic phonons in two-dimensional crystals |
Type |
A1 Journal article |
| |
Year |
2015 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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| |
Volume |
91 |
Issue |
91 |
Pages |
134302 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
Anharmonic effects in an atomic monolayer thin crystal with honeycomb lattice structure are investigated by analytical and numerical lattice dynamical methods. Starting from a semiempirical model for anharmonic couplings of third and fourth orders, we study the in-plane and out-of-plane (flexural) mode components of the generalized wave vector dependent Gruneisen parameters, the thermal tension and the thermal expansion coefficients as a function of temperature and crystal size. From the resonances of the displacement-displacement correlation functions, we obtain the renormalization and decay rate of in-plane and flexural phonons as a function of temperature, wave vector, and crystal size in the classical and in the quantum regime. Quantitative results are presented for graphene. There, we find that the transition temperature T-alpha from negative to positive thermal expansion is lowered with smaller system size. Renormalization of the flexural mode has the opposite effect and leads to values of T-alpha approximate to 300 K for systems of macroscopic size. Extensive numerical analysis throughout the Brillouin zone explores various decay and scattering channels. The relative importance of normal and umklapp processes is investigated. The work is complementary to crystalline membrane theory and computational studies of anharmonic effects in two-dimensional crystals. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
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| |
Language |
|
Wos |
000353031000001 |
Publication Date |
2015-04-17 |
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| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1098-0121; 1550-235x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
38 |
Open Access |
|
|
| |
Notes |
; We thank B. Verberck, D. Lamoen, and A. Dobry for useful comments. We acknowledge funding from the FWO (Belgium)-MINCyT (Argentina) collaborative research project. This work is supported by the EuroGRAPHENE project CONGRAN. ; |
Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
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| |
Call Number |
UA @ lucian @ c:irua:132512 |
Serial |
4263 |
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| Permanent link to this record |
| |
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| |
|
Author |
Michel, K.H.; Costamagna; Peeters, F.M. |
|
| |
Title |
Theory of thermal expansion in 2D crystals |
Type |
A1 Journal article |
| |
Year |
2015 |
Publication |
Physica status solidi: B: basic research |
Abbreviated Journal |
Phys Status Solidi B |
|
| |
Volume |
252 |
Issue |
252 |
Pages |
2433-2437 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
The thermal expansion alpha(T) in layered crystals is of fundamental and technological interest. As suggested by I. M. Lifshitz in 1952, in thin solid films (crystalline membranes) a negative contribution to alpha(T) is due to anharmonic couplings between in-plane stretching modes and out-of-plane bending (flexural modes). Genuine in-plane anharmonicities give a positive contribution to alpha(T). The competition between these two effects can lead to a change of sign (crossover) from a negative value of alpha(T) in a temperature (T) range T <= T-alpha to a positive value of alpha(T) for T > T-alpha in layered crystals. Here, we present an analytical lattice dynamical theory of these phenomena for a two-dimensional (2D) hexagonal crystal. We start from a Hamiltonian that comprises anharmonic terms of third and fourth order in the lattice displacements. The in-plane and out-of-plane contributions to the thermal expansion are studied as functions of T for crystals of different sizes. Besides, renormalization of the flexural mode frequencies plays a crucial role in determining the crossover temperature T-alpha. Numerical examples are given for graphene where the anharmonic couplings are determined from experiments. The theory is applicable to other layer crystals wherever the anharmonic couplings are known. (C) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Berlin |
Editor |
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| |
Language |
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Wos |
000364690400014 |
Publication Date |
2015-08-06 |
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| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0370-1972 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
1.674 |
Times cited |
21 |
Open Access |
|
|
| |
Notes |
; We thank B. Verberck, D. Lamoen, and A. Dobry for useful comments. We acknowledge funding from the FWO (Belgium)-MINCyT (Argentina) collaborative research project. This work is supported by the Euro GRAPHENE project CONGRAN. ; |
Approved |
Most recent IF: 1.674; 2015 IF: 1.489 |
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| |
Call Number |
UA @ lucian @ c:irua:130281 |
Serial |
4264 |
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| Permanent link to this record |
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| |
|
Author |
Michel, K.H.; Copley, J.R.D.; Neumann, D.A. |
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| |
Title |
Microscopic theory of orientational disorder and the orientational phase transition in solid C60 |
Type |
A1 Journal article |
| |
Year |
1992 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
|
| |
Volume |
68 |
Issue |
19 |
Pages |
2929-2932 |
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| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
We have developed a microscopic theory which describes the orientational dynamics of C60 molecules in the face-centered-cubic phase of C60 fullerite. The molecular interaction potential and the crystal-field potential are formulated in terms of symmetry-adapted rotator functions. The phase transition to the Pa3BAR structure is driven by an active multipolar mode of T2g symmetry belonging to the l = 10 manifold. The Birman criterion is satisfied. The transition is found to be of first order. |
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| |
Address |
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Corporate Author |
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Thesis |
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| |
Publisher |
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Place of Publication |
New York, N.Y. |
Editor |
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| |
Language |
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Wos |
A1992HT64800019 |
Publication Date |
2002-07-27 |
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| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0031-9007; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
7.512 |
Times cited |
94 |
Open Access |
|
|
| |
Notes |
|
Approved |
|
|
| |
Call Number |
UA @ lucian @ c:irua:95492 |
Serial |
2032 |
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| Permanent link to this record |
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| |
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Author |
Michel, K.H.; Çakir, D.; Sevik, C.; Peeters, F.M. |
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| |
Title |
Piezoelectricity in two-dimensional materials : comparative study between lattice dynamics and ab initio calculations |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
95 |
Issue |
95 |
Pages |
125415 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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| |
Abstract |
The elastic constant C-11 and piezoelectric stress constant e(1),(11) of two-dimensional (2D) dielectric materials comprising h-BN, 2H-MoS2, and other transition-metal dichalcogenides and dioxides are calculated using lattice dynamical theory. The results are compared with corresponding quantities obtained with ab initio calculations. We identify the difference between clamped-ion and relaxed-ion contributions with the dependence on inner strains which are due to the relative displacements of the ions in the unit cell. Lattice dynamics allows us to express the inner-strain contributions in terms of microscopic quantities such as effective ionic charges and optoacoustical couplings, which allows us to clarify differences in the piezoelectric behavior between h-BN and MoS2. Trends in the different microscopic quantities as functions of atomic composition are discussed. |
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| |
Address |
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Corporate Author |
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Thesis |
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| |
Publisher |
American Physical Society |
Place of Publication |
New York, N.Y |
Editor |
|
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| |
Language |
|
Wos |
000396013400005 |
Publication Date |
2017-03-11 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2469-9969; 2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
29 |
Open Access |
|
|
| |
Notes |
; The authors acknowledge useful discussions with L. Wirtz and A. Molina-Sanchez. This work was supported by the Methusalem program and the Fonds voor Wetenschappelijk Onderzoek-Vlaanderen. Computational resources were provided by HPC infrastructure of the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center (VSC), which is funded by the Hercules foundation. ; |
Approved |
Most recent IF: 3.836 |
|
| |
Call Number |
UA @ lucian @ c:irua:142444 |
Serial |
4603 |
|
| Permanent link to this record |
