| |
Records |
Links |
|
Author  |
Moldovan, D. |
|
| |
Title |
Electronic properties of strained graphene and supercritical charge centers |
Type |
Doctoral thesis |
| |
Year |
2016 |
Publication |
|
Abbreviated Journal |
|
|
| |
Volume |
|
Issue |
|
Pages |
|
|
| |
Keywords |
Doctoral thesis; Condensed Matter Theory (CMT) |
|
| |
Abstract |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Antwerpen |
Editor |
|
|
| |
Language |
|
Wos |
|
Publication Date |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Additional Links |
UA library record |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: NA |
|
| |
Call Number |
UA @ lucian @ c:irua:135792 |
Serial |
4352 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Moldovan, D.; Masir, M.R.; Covaci, L.; Peeters, F.M. |
|
| |
Title |
Resonant valley filtering of massive Dirac electrons |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
86 |
Issue |
11 |
Pages |
115431 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Electrons in graphene, in addition to their spin, have two pseudospin degrees of freedom: sublattice and valley pseudospin. Valleytronics uses the valley degree of freedom as a carrier of information similarly to the way spintronics uses electron spin. We show how a double-barrier structure consisting of electric and vector potentials can be used to filter massive Dirac electrons based on their valley index. We study the resonant transmission through a finite number of barriers and we obtain the energy spectrum of a superlattice consisting of electric and vector potentials. When a mass term is included, the energy bands and energy gaps at the K and K′ points are different and they can be tuned by changing the potential. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000309173300004 |
Publication Date |
2012-09-21 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
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 |
55 |
Open Access |
|
|
| |
Notes |
This work was supported by the European Science Foundation (ESF) under the EUROCORES Program Euro- GRAPHENE within the project CONGRAN, and the Flemish Science Foundation (FWO-Vl). |
Approved |
Most recent IF: 3.836; 2012 IF: 3.767 |
|
| |
Call Number |
UA @ lucian @ c:irua:101835 |
Serial |
2896 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Moldovan, D.; Masir, M.R.; Peeters, F.M. |
|
| |
Title |
Electronic states in a graphene flake strained by a Gaussian bump |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
88 |
Issue |
3 |
Pages |
035446-35447 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The effect of strain in graphene is usually modeled by a pseudomagnetic vector potential which is, however, derived in the limit of small strain. In realistic cases deviations are expected in view of graphene's very high strain tolerance, which can be up to 25%. Here we investigate the pseudomagnetic field generated by a Gaussian bump and we show that it exhibits significant differences with numerical tight-binding results. Furthermore, we calculate the electronic states in the strained region for a hexagon shaped flake with armchair edges. We find that the sixfold symmetry of the wave functions inside the Gaussian bump is directly related to the different effects of strain along the fundamental directions of graphene: zigzag and armchair. Low energy electrons are strongly confined in the armchair directions and are localized on the carbon atoms of a single sublattice. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000322587500003 |
Publication Date |
2013-07-30 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
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 |
50 |
Open Access |
|
|
| |
Notes |
; This work was supported by the European Science Foundation (ESF) under the EUROCORES Program Euro-GRAPHENE within the project CONGRAN, the Flemish Science Foundation (FWO-Vl), and the Methusalem Funding of the Flemish Government. ; |
Approved |
Most recent IF: 3.836; 2013 IF: 3.664 |
|
| |
Call Number |
UA @ lucian @ c:irua:109800 |
Serial |
1007 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Moldovan, D.; Masir, M.R.; Peeters, F.M. |
|
| |
Title |
Magnetic field dependence of the atomic collapse state in graphene |
Type |
A1 Journal article |
| |
Year |
2018 |
Publication |
2D materials |
Abbreviated Journal |
2D Mater |
|
| |
Volume |
5 |
Issue |
1 |
Pages |
015017 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
<script type='text/javascript'>document.write(unpmarked('Quantum electrodynamics predicts that heavy atoms (Z \u003E Z(c) approximate to 170) will undergo the process of atomic collapse where electrons sink into the positron continuum and a new family of so-called collapsing states emerges. The relativistic electrons in graphene exhibit the same physics but at a much lower critical charge (Z(c) approximate to 1) which has made it possible to confirm this phenomenon experimentally. However, there exist conflicting predictions on the effect of a magnetic field on atomic collapse. These theoretical predictions are based on the continuum Dirac-Weyl equation, which does not have an exact analytical solution for the interplay of a supercritical Coulomb potential and the magnetic field. Approximative solutions have been proposed, but because the two effects compete on similar energy scales, the theoretical treatment varies depending on the regime which is being considered. These limitations are overcome here by starting from a tight-binding approach and computing exact numerical results. By avoiding special limit cases, we found a smooth evolution between the different regimes. We predict that the atomic collapse effect persists even after the magnetic field is activated and that the critical charge remains unchanged. We show that the atomic collapse regime is characterized: (1) by a series of Landau level anticrossings and (2) by the absence of root B scaling of the Landau levels with regard to magnetic field strength.')); |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
IOP Publishing |
Place of Publication |
Bristol |
Editor |
|
|
| |
Language |
|
Wos |
000415015000001 |
Publication Date |
2017-10-26 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2053-1583 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
6.937 |
Times cited |
13 |
Open Access |
|
|
| |
Notes |
; We thank Eva Andrei, Jinhai Mao and Yuhang Jiang for insightful discussions. This work was supported by the Flemish Science Foundation (FWO-Vl) and the Methusalem Funding of the Flemish Government. ; |
Approved |
Most recent IF: 6.937 |
|
| |
Call Number |
UA @ lucian @ c:irua:147361UA @ admin @ c:irua:147361 |
Serial |
4884 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Moldovan, D.; Peeters, F.M. |
|
| |
Title |
Strain engineering of the electronic properties of bilayer graphene quantum dots: Strain engineering of the electronic properties of bilayer graphene quantum dots |
Type |
A1 Journal article |
| |
Year |
2015 |
Publication |
Physica status solidi: rapid research letters |
Abbreviated Journal |
Phys Status Solidi-R |
|
| |
Volume |
10 |
Issue |
10 |
Pages |
39-45 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
We study the effect of mechanical deformations on the elec- tronic properties of hexagonal flakes of bilayer graphene. The behavior of electrons induced by triaxial strain can be de- scribed by an effective pseudo-magnetic field which is homo- geneous in the center of the flake. We find that in-plane strain, applied to both layers equally, can break the layer symmetry leading to different behavior in the top and bottom layers of graphene. At low energy, just one of the layers feels
the pseudo-magnetic field: the zero-energy pseudo-Landau level is missing in the second layer, thus creating a gap be- tween the lowest non-zero levels. While the layer asymmetry is most significant at zero energy, interaction with the edges of the flake extends the effect to higher pseudo-Landau lev- els. The behavior of the top and bottom layers may be re- versed by rotating the triaxial strain by 60°. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000368814500005 |
Publication Date |
2015-08-18 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1862-6254; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.032 |
Times cited |
9 |
Open Access |
|
|
| |
Notes |
This work was supported by the European Science Foundation (ESF) under the EUROCORES Program EuroGRAPHENE within the project CONGRAN, the Flemish Science Foundation (FWO-Vl) and the Methusalem Funding of the Flemish Government. |
Approved |
Most recent IF: 3.032; 2015 IF: 2.142 |
|
| |
Call Number |
c:irua:129592 |
Serial |
3970 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Moldovan, D.; Peeters, F.M. |
|
| |
Title |
Atomic Collapse in Graphene |
Type |
P1 Proceeding |
| |
Year |
2016 |
Publication |
Nanomaterials For Security |
Abbreviated Journal |
|
|
| |
Volume |
|
Issue |
|
Pages |
3-17 |
|
| |
Keywords |
P1 Proceeding; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
|
| |
Abstract |
When the charge Z of an atom exceeds the critical value of 170, it will undergo a process called atomic collapse which triggers the spontaneous creation of electron-positron pairs. The high charge requirements have prevented the observation of this phenomenon with real atomic nuclei. However, thanks to the relativistic nature of the carriers in graphene, the same physics is accessible at a much lower scale. The atomic collapse analogue in graphene is realized using artificial nuclei which can be created via the deposition of impurities on the surface of graphene or using charged vacancies. These supercritically charged artificial nuclei trap electrons in a sequence of quasi-bound states which can be observed experimentally as resonances in the local density of states. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
Springer |
Place of Publication |
Dordrecht |
Editor |
|
|
| |
Language |
|
Wos |
000386506200001 |
Publication Date |
2016-07-20 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
978-94-017-7593-9; 978-94-017-7591-5 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
|
Times cited |
3 |
Open Access |
|
|
| |
Notes |
; ; |
Approved |
Most recent IF: NA |
|
| |
Call Number |
UA @ lucian @ c:irua:138237 |
Serial |
4348 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Molina, L.; Egoavil, R.; Turner, S.; Thersleff, T.; Verbeeck, J.; Holzapfel, B.; Eibl, O.; Van Tendeloo, G. |
|
| |
Title |
Interlayer structure in YBCO-coated conductors prepared by chemical solution deposition |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Superconductor science and technology |
Abbreviated Journal |
Supercond Sci Tech |
|
| |
Volume |
26 |
Issue |
7 |
Pages |
075016-75018 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
The functionality of YBa2Cu3O7−δ (YBCO)-coated conductor technology depends on the reliability and microstructural properties of a given tape or wire architecture. Particularly, the interface to the metal tape is of interest since it determines the adhesion, mechanical stability of the film and thermal contact of the film to the substrate. A trifluoroacetate (TFA)metal organic deposition (MOD) prepared YBCO film deposited on a chemical solution-derived buffer layer architecture based on CeO2/La2Zr2O7 and grown on a flexible Ni5 at.%W substrate with a {100}⟨001⟩ biaxial texture was investigated. The YBCO film had a thickness was 440 nm and a jc of 1.02 MA cm−2 was determined at 77 K and zero external field. We present a sub-nanoscale analysis of a fully processed solution-derived YBCO-coated conductor by aberration-corrected scanning transmission electron microscopy (STEM) combined with electron energy-loss spectroscopy (EELS). For the first time, structural and chemical analysis of the valence has been carried out on the sub-nm scale. Intermixing of Ni, La, Ce, O and Ba takes place at these interfaces and gives rise to nanometer-sized interlayers which are a by-product of the sequential annealing process. Two distinct interfacial regions were analyzed in detail: (i) the YBCO/CeO2/La2Zr2O7 region (10 nm interlayer) and (ii) the La2Zr2O7/Ni5 at.%W substrate interface region (20 nm NiO). This is of particular significance for the functionality of these YBCO-coated conductor architectures grown by chemical solution deposition. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Bristol |
Editor |
|
|
| |
Language |
|
Wos |
000319973800024 |
Publication Date |
2013-05-28 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0953-2048;1361-6668; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.878 |
Times cited |
11 |
Open Access |
|
|
| |
Notes |
vortex; Countatoms; Fwo; Esteem2; esteem2jra2; esteem2jra3 ECASJO_; |
Approved |
Most recent IF: 2.878; 2013 IF: 2.796 |
|
| |
Call Number |
UA @ lucian @ c:irua:108704UA @ admin @ c:irua:108704 |
Serial |
1698 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Molina, L.; Tan, H.; Biermans, E.; Batenburg, K.J.; Verbeeck, J.; Bals, S.; Van Tendeloo, G. |
|
| |
Title |
Barrier efficiency of sponge-like La2Zr2O7 buffer layers for YBCO-coated conductors |
Type |
A1 Journal article |
| |
Year |
2011 |
Publication |
Superconductor science and technology |
Abbreviated Journal |
Supercond Sci Tech |
|
| |
Volume |
24 |
Issue |
6 |
Pages |
065019-065019,8 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
|
| |
Abstract |
Solution derived La2Zr2O7 films have drawn much attention for potential applications as thermal barriers or low-cost buffer layers for coated conductor technology. Annealing and coating parameters strongly affect the microstructure of La2Zr2O7, but different film processing methods can yield similar microstructural features such as nanovoids and nanometer-sized La2Zr2O7 grains. Nanoporosity is a typical feature found in such films and the implications for the functionality of the films are investigated by a combination of scanning transmission electron microscopy (STEM), electron energy-loss spectroscopy (EELS) and quantitative electron tomography. Chemical solution based La2Zr2O7 films deposited on flexible Ni5 at.%W substrates with a {100}lang001rang biaxial texture were prepared for an in-depth characterization. A sponge-like structure composed of nanometer-sized voids is revealed by high-angle annular dark-field scanning transmission electron microscopy in combination with electron tomography. A three-dimensional quantification of nanovoids in the La2Zr2O7 film is obtained on a local scale. Mostly non-interconnected highly faceted nanovoids compromise more than one-fifth of the investigated sample volume. The diffusion barrier efficiency of a 170 nm thick La2Zr2O7 film is investigated by STEM-EELS, yielding a 1.8 ± 0.2 nm oxide layer beyond which no significant nickel diffusion can be detected and intermixing is observed. This is of particular significance for the functionality of YBa2Cu3O7 − δ coated conductor architectures based on solution derived La2Zr2O7 films as diffusion barriers. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Bristol |
Editor |
|
|
| |
Language |
|
Wos |
000290472900021 |
Publication Date |
2011-04-20 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0953-2048;1361-6668; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.878 |
Times cited |
31 |
Open Access |
|
|
| |
Notes |
Esteem 026019; Fwo |
Approved |
Most recent IF: 2.878; 2011 IF: 2.662 |
|
| |
Call Number |
UA @ lucian @ c:irua:88639UA @ admin @ c:irua:88639 |
Serial |
221 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Molina-Luna, L.; Duerrschnabel, M.; Turner, S.; Erbe, M.; Martinez, G.T.; Van Aert, S.; Holzapfel, B.; Van Tendeloo, G. |
|
| |
Title |
Atomic and electronic structures of BaHfO3-doped TFA-MOD-derived YBa2Cu3O7−δthin films |
Type |
A1 Journal article |
| |
Year |
2015 |
Publication |
Superconductor science and technology |
Abbreviated Journal |
Supercond Sci Tech |
|
| |
Volume |
28 |
Issue |
28 |
Pages |
115009 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
| |
Abstract |
Tailoring the properties of oxide-based nanocomposites is of great importance for a wide range of materials relevant for energy technology. YBa2Cu3O7−δ (YBCO) superconducting thin films containing nanosized BaHfO3 (BHO) particles yield a significant improvement of the magnetic flux pinning properties and a reduced anisotropy of the critical current density. These films were prepared by chemical solution deposition (CSD) on (100) SrTiO3 (STO) substrates yielding critical current densities up to 3.6 MA cm−2 at 77 K and self-field. Transport in-field J c measurements demonstrated a high pinning force maximum of around 6 GN/m3 for a sample annealed at T = 760 °C that has a doping of 12 mol% of BHO. This sample was investigated by scanning transmission electron microscopy (STEM) in combination with electron energy-loss spectroscopy (EELS) yielding strain and spectral maps. Spherical BHO nanoparticles of 15 nm in size were found in the matrix, whereas the particles at the interface were flat. A 2 nm diffusion layer containing Ti was found at the YBCO (BHO)/STO interface. Local lattice deformation mapping at the atomic scale revealed crystal defects induced by the presence of both sorts of BHO nanoparticles, which can act as pinning centers for magnetic flux lines. Two types of local lattice defects were identified and imaged: (i) misfit edge dislocations and (ii) Ba-Cu-Cu-Ba stacking faults (Y-248 intergrowths). The local electronic structure and charge transfer were probed by high energy resolution monochromated electron energy-loss spectroscopy. This technique made it possible to distinguish superconducting from non-superconducting areas in nanocomposite samples with atomic resolution in real space, allowing the identification of local pinning sites on the order of the coherence length of YBCO (~1.5 nm) and the determination of 0.25 nm dislocation cores. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000366193000018 |
Publication Date |
2015-09-25 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0953-2048;1361-6668; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.878 |
Times cited |
4 |
Open Access |
|
|
| |
Notes |
The authors thank financial support from the European Union under the Framework 6 program as a contract for an Integrated Infrastructure Initiative (References No. 026019 ESTEEM) and by the EUFP6 Research Project “NanoEngineered Superconductors for Power Applications” NESPA no. MRTN-CT-2006-035619. This work was supported by funding from the European Research Council under the Seventh Framework Programme (FP7). L.M.L, S.T. and G.V.T acknowledge ERC grant N°246791 – COUNTATOMS and funding under a contract for an Integrated Infrastructure Initiative, Reference No. 312483- ESTEEM2, as well as the EC project EUROTAPES. G.T.M. and S.V.A acknowledge financial support from the Fund for Scientific Research-Flanders (Reference G.0064.10N and G.0393.11N). M.D. acknowledges financial support from the LOEWE research cluster RESPONSE (Hessen, Germany). M.E. has received funding from the European Union Seventh Framework Programme (FP7/2007–2013) under grant agreement n° NMP-LA-2012-280432.; esteem2jra2; esteem2jra3 |
Approved |
Most recent IF: 2.878; 2015 IF: 2.325 |
|
| |
Call Number |
c:irua:129199 c:irua:129199 |
Serial |
3942 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Molnár, B.; Peeters, F.M.; Vasilopoulos, P. |
|
| |
Title |
Spin-dependent magnetotransport through a ring due to spin-orbit interaction |
Type |
A1 Journal article |
| |
Year |
2004 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
69 |
Issue |
|
Pages |
155335,1-11 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
|
|
| |
Language |
|
Wos |
000221426800104 |
Publication Date |
2004-04-30 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
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 |
199 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 3.836; 2004 IF: 3.075 |
|
| |
Call Number |
UA @ lucian @ c:irua:69385 |
Serial |
3083 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Molnár, B.; Vasilopoulos, P.; Peeters, F.M. |
|
| |
Title |
Magnetoconductance through a chain of rings with or without periodically modulated spin-orbit interaction strength and magnetic field |
Type |
A1 Journal article |
| |
Year |
2005 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
72 |
Issue |
|
Pages |
075330,1-7 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
|
|
| |
Language |
|
Wos |
000231564500117 |
Publication Date |
2005-08-12 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
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 |
52 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 3.836; 2005 IF: 3.185 |
|
| |
Call Number |
UA @ lucian @ c:irua:69414 |
Serial |
1915 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Molnar, B.; Vasilopoulos, P.; Peeters, F.M. |
|
| |
Title |
Spin-dependent transmission through a chain of rings : influence of a periodically modulated spin-orbit interaction strength or ring radius |
Type |
A1 Journal article |
| |
Year |
2004 |
Publication |
Applied physics letters |
Abbreviated Journal |
Appl Phys Lett |
|
| |
Volume |
85 |
Issue |
4 |
Pages |
612-614 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
We study ballistic electron transport through a finite chain of quantum circular rings in the presence of spin-orbit interaction of strength alpha. For a single ring, the transmission and reflection coefficients are obtained analytically and from them the conductance for a chain of rings as a function of alpha and of the wave vector k of the incident electron. We show that due to destructive spin interferences, the chain can be totally opaque for certain ranges of k, the width of which depends on the value of alpha. A periodic modulation of the strength alpha or of the ring radius widens the gaps considerably and produces a nearly binary conductance output. (C) 2004 American Institute of Physics. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
|
|
| |
Language |
|
Wos |
000222855400034 |
Publication Date |
2004-07-23 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0003-6951; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.411 |
Times cited |
26 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 3.411; 2004 IF: 4.308 |
|
| |
Call Number |
UA @ lucian @ c:irua:94799 |
Serial |
3085 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Molnar, B.; Vasilopoulos, P.; Peeters, F.M. |
|
| |
Title |
Square-wave conductance through a chain of rings due to spin-orbit interaction |
Type |
P1 Proceeding |
| |
Year |
2005 |
Publication |
AIP conference proceedings |
Abbreviated Journal |
|
|
| |
Volume |
772 |
Issue |
|
Pages |
1335-1336 |
|
| |
Keywords |
P1 Proceeding; Condensed Matter Theory (CMT) |
|
| |
Abstract |
We study ballistic electron transport through a finite chain of quantum circular rings in the presence of spin-orbit interaction (SOI) of strength alpha. The transmission and reflection coefficients for a single ring, obtained analytical lylead to the conductance for a chain of rings as a function of alpha and of the wave vector k of the incident electron. Due to destructive spin interferences the chain can be totaly opaque for certain ranges of k the width of which depends on the value of alpha. A periodic modulation of a widens up the gaps considerably and produces a nearly binary conductance output. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
New York |
Editor |
|
|
| |
Language |
|
Wos |
|
Publication Date |
0000-00-00 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0094-243x |
ISBN |
|
Additional Links |
UA library record; WoS full record; |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: NA |
|
| |
Call Number |
UA @ lucian @ c:irua:94771 |
Serial |
3113 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Momot, A.; Amini, M.N.; Reekmans, G.; Lamoen, D.; Partoens, B.; Slocombe, D.R.; Elen, K.; Adriaensens, P.; Hardy, A.; Van Bael, M.K. |
|
| |
Title |
A novel explanation for the increased conductivity in annealed Al-doped ZnO: an insight into migration of aluminum and displacement of zinc |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Physical chemistry, chemical physics |
Abbreviated Journal |
Phys Chem Chem Phys |
|
| |
Volume |
19 |
Issue |
40 |
Pages |
27866-27877 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
|
| |
Abstract |
A combined experimental and first-principles study is performed to study the origin of conductivity in
ZnO:Al nanoparticles synthesized under controlled conditions via a reflux route using benzylamine as a
solvent. The experimental characterization of the samples by Raman, nuclear magnetic resonance (NMR)
and conductivity measurements indicates that upon annealing in nitrogen, the Al atoms at interstitial
positions migrate to the substitutional positions, creating at the same time Zn interstitials. We provide
evidence for the fact that the formed complex of AlZn and Zni corresponds to the origin of the Knight
shifted peak (KS) we observe in 27Al NMR. As far as we know, the role of this complex has not been
discussed in the literature to date. However, our first-principles calculations show that such a complex is
indeed energetically favoured over the isolated Al interstitial positions. In our calculations we also
address the charge state of the Al interstitials. Further, Zn interstitials can migrate from Al_Zn and possibly
also form Zn clusters, leading to the observed increased conductivity. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000413290500073 |
Publication Date |
2017-10-09 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1463-9076 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.123 |
Times cited |
26 |
Open Access |
OpenAccess |
|
| |
Notes |
We want to thank the Interuniversity Attraction Poles Programme (P7/05) initiated by the Belgian Science Policy Office (BELSPO) for the financial support. We also acknowledge the Research Foundation Flanders (FWO-Vlaanderen) for support via the MULTIMAR WOG project and under project No. G018914. The computational parts were carried out using the HPC infrastructure at the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center VSC, supported financially by the Hercules foundation and the Flemish Government (EWI Department). |
Approved |
Most recent IF: 4.123 |
|
| |
Call Number |
EMAT @ emat @c:irua:146878 |
Serial |
4760 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Monai, M.; Jenkinson, K.; Melcherts, A.E.M.; Louwen, J.N.; Irmak, E.A.; Van Aert, S.; Altantzis, T.; Vogt, C.; van der Stam, W.; Duchon, T.; Smid, B.; Groeneveld, E.; Berben, P.; Bals, S.; Weckhuysen, B.M. |
|
| |
Title |
Restructuring of titanium oxide overlayers over nickel nanoparticles during catalysis |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
Science |
Abbreviated Journal |
|
|
| |
Volume |
380 |
Issue |
6645 |
Pages |
644-651 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT) |
|
| |
Abstract |
Reducible supports can affect the performance of metal catalysts by the formation of suboxide overlayers upon reduction, a process referred to as the strong metal-support interaction (SMSI). A combination of operando electron microscopy and vibrational spectroscopy revealed that thin TiOx overlayers formed on nickel/titanium dioxide catalysts during 400 degrees C reduction were completely removed under carbon dioxide hydrogenation conditions. Conversely, after 600 degrees C reduction, exposure to carbon dioxide hydrogenation reaction conditions led to only partial reexposure of nickel, forming interfacial sites in contact with TiOx and favoring carbon-carbon coupling by providing a carbon species reservoir. Our findings challenge the conventional understanding of SMSIs and call for more-detailed operando investigations of nanocatalysts at the single-particle level to revisit static models of structure-activity relationships. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000999020900010 |
Publication Date |
2023-05-11 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0036-8075; 1095-9203 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
56.9 |
Times cited |
29 |
Open Access |
OpenAccess |
|
| |
Notes |
This work was supported by BASF and NWO CHIPP (research grant to B.M.W.); the MCEC NWO Gravitation Program (B.M.W.); the ARC-CBBC NWO Program (B.M.W.); the European Research Council (grant 770887 PICOMETRICS to S.V.A.); and the European Research Council (grant 815128 REALNANO to S.B.). |
Approved |
Most recent IF: 56.9; 2023 IF: 37.205 |
|
| |
Call Number |
UA @ admin @ c:irua:197432 |
Serial |
8923 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Monarkha, Y.P.; Peeters, F.M. |
|
| |
Title |
Nonlinear-cold-quantum magnetotransport in a nondegenerate two-dimensional electron gas |
Type |
A1 Journal article |
| |
Year |
1996 |
Publication |
Europhysics letters |
Abbreviated Journal |
Epl-Europhys Lett |
|
| |
Volume |
34 |
Issue |
|
Pages |
611-616 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Paris |
Editor |
|
|
| |
Language |
|
Wos |
A1996UT81900010 |
Publication Date |
2003-12-18 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0295-5075;1286-4854; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.095 |
Times cited |
4 |
Open Access |
|
|
| |
Notes |
|
Approved |
COMPUTER SCIENCE, INTERDISCIPLINARY 11/104 Q1 # PHYSICS, MATHEMATICAL 1/53 Q1 # |
|
| |
Call Number |
UA @ lucian @ c:irua:15796 |
Serial |
2351 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Monarkha, Y.P.; Peeters, F.M.; Sokolov, S.S. |
|
| |
Title |
Edge excitations of a 2D electron solid in a magnetic field |
Type |
A1 Journal article |
| |
Year |
1997 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
|
| |
Volume |
9 |
Issue |
|
Pages |
1537-1545 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
London |
Editor |
|
|
| |
Language |
|
Wos |
A1997WK00500016 |
Publication Date |
0000-00-00 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0953-8984 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.649 |
Times cited |
1 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 2.649; 1997 IF: 1.479 |
|
| |
Call Number |
UA @ lucian @ c:irua:19294 |
Serial |
787 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Monarkha, Y.P.; Shirahama, K.; Kono, K.; Peeters, F.M. |
|
| |
Title |
Nonlinear quantum magnetotransport in a strongly correlated two-dimensional electron liquid |
Type |
A1 Journal article |
| |
Year |
1998 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
58 |
Issue |
|
Pages |
3762-3776 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
|
|
| |
Language |
|
Wos |
000075616800057 |
Publication Date |
2002-07-27 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0163-1829;1095-3795; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
4 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 3.836; 1998 IF: NA |
|
| |
Call Number |
UA @ lucian @ c:irua:24163 |
Serial |
2354 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Monico, L.; Cartechini, L.; Rosi, F.; Chieli, A.; Grazia, C.; De Meyer, S.; Nuyts, G.; Vanmeert, F.; Janssens, K.; Cotte, M.; De Nolf, W.; Falkenberg, G.; Sandu, I.C.A.; Tveit, E.S.; Mass, J.; De Freitas, R.P.; Romani, A.; Miliani, C. |
|
| |
Title |
Probing the chemistry of CdS paints in The Scream by in situ noninvasive spectroscopies and synchrotron radiation x-ray techniques |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Science Advances |
Abbreviated Journal |
|
|
| |
Volume |
6 |
Issue |
20 |
Pages |
eaay3514 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
|
| |
Abstract |
The degradation of cadmium sulfide (CdS)-based oil paints is a phenomenon potentially threatening the iconic painting The Scream (ca. 1910) by Edvard Munch (Munch Museum, Oslo) that is still poorly understood. Here, we provide evidence for the presence of cadmium sulfate and sulfites as alteration products of the original CdS-based paint and explore the external circumstances and internal factors causing this transformation. Macroscale in situ noninvasive spectroscopy studies of the painting in combination with synchrotron-radiation x-ray microspectroscopy investigations of a microsample and artificially aged mock-ups show that moisture and mobile chlorine compounds are key factors for promoting the oxidation of CdS, while light (photodegradation) plays a less important role. Furthermore, under exposure to humidity, parallel/secondary reactions involving dissolution, migration through the paint, and recrystallization of water-soluble phases of the paint are associated with the formation of cadmium sulfates. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000533573300009 |
Publication Date |
2020-05-16 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2375-2548 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
13.6 |
Times cited |
4 |
Open Access |
|
|
| |
Notes |
; The research was financially supported by the European research project IPERION-CH, funded by the European Commission, H2020-INFRAIA-2014-2015 (grant agreement no. 654028); the project AMIS, within the program Dipartimenti di Eccellenza 2018-2022 (funded by MIUR and University of Perugia); and the program “Ricerca di Base 2017” (funded by University of Perugia). S.D.M. and K.J. acknowledge the GOA Project SolarPaint from the University of Antwerp Research Council and projects G056619N and G054719N from FWO (Brussels). F.V. and K.J. acknowledge support from Interreg Project Smart*Light and thank BELSPO (Brussels) for financial support via FED-tWIN mandate PRF055. L.M. acknowledges the Erasmus+ program (Staff Mobility for training, A. Y. 2018 to 2019) of the European Commission. In situ noninvasive analyses were performed using the European MOLAB platform, which is financially supported by the European project IPERION-CH. For the beamtime grants received, the authors thank the ESRF-ID21 beamline (experiment nos. HG32, HG64, and HG95), DESY-P06 beamline, a member of the Helmholtz Association HGF (experiment nos. I-20130221 EC and I-20160126 EC), and the project CALIPSOplus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020. ; |
Approved |
Most recent IF: 13.6; 2020 IF: NA |
|
| |
Call Number |
UA @ admin @ c:irua:169519 |
Serial |
6585 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Monico, L.; Chieli, A.; De Meyer, S.; Cotte, M.; de Nolf, W.; Falkenberg, G.; Janssens, K.; Romani, A.; Miliani, C. |
|
| |
Title |
Role of the relative humidity and the Cd/Zn stoichiometry in the photooxidation process of cadmium yellows (CdS/Cd1-xZnxS) in oil paintings |
Type |
A1 Journal article |
| |
Year |
2018 |
Publication |
Chemistry: a European journal |
Abbreviated Journal |
Chem-Eur J |
|
| |
Volume |
24 |
Issue |
45 |
Pages |
11584-11593 |
|
| |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
|
| |
Abstract |
Cadmium yellows (CdYs) refer to a family of cadmium sulfide pigments, which have been widely used by artists since the late 19th century. Despite being considered stable, they are suffering from discoloration in iconic paintings, such as Joy of Life by Matisse, Flowers in a blue vase by Van Gogh, and The Scream by Munch, most likely due to the formation of CdSO4 center dot nH(2)O. The driving factors of the CdYs degradation and how these affect the overall process are still unknown. Here, we study a series of oil mock-up paints made of CdYs of different stoichiometry (CdS/Cd0.76Zn0.24S) and crystalline structure (hexagonal/ cubic) before and after aging at variable relative humidity under exposure to light and in darkness. Synchrotron radiation-based X-ray methods combined with UV-Vis and FTIR spectroscopy show that: 1) Cd0.76Zn0.24S is more susceptible to photooxidation than CdS; both compounds can act as photocatalysts for the oil oxidation. 2) The photooxidation of CdS/Cd0.76Zn0.24S to CdSO4 center dot nH(2)O is triggered by moisture. 3) The nature of alteration products depends on the aging conditions and the Cd/Zn stoichiometry. Based on our findings, we propose a scheme for the mechanism of the photocorrosion process and the photocatalytic activity of CdY pigments in the oil binder. Overall, our results form a reliable basis for understanding the degradation of CdS-based paints in artworks and contribute towards developing better ways of preserving them for future generations. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000441126900012 |
Publication Date |
2018-06-06 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0947-6539 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
5.317 |
Times cited |
5 |
Open Access |
|
|
| |
Notes |
; The research was financially supported by the European research project IPERION-CH, funded by the European Commission, H2020-INFRAIA-2014-2015 (Grant agreement n. 654028) and by the BOF-GOA Project SOLARPaint (University of Antwerp Research Council). For the beamtime grants received, we thank the ESRF (experiments n. HG64, HG95 and in-house beamtimes) and PETRA III-DESY (experiments: I-20130221 EC, I-20160126 EC). We are also grateful to Dr. Jan Garrevoet for his contribution to set up the P06-beamline at PETRA III-DESY. ; |
Approved |
Most recent IF: 5.317 |
|
| |
Call Number |
UA @ admin @ c:irua:153733 |
Serial |
5821 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Monico, L.; Cotte, M.; Vanmeert, F.; Amidani, L.; Janssens, K.; Nuyts, G.; Garrevoet, J.; Falkenberg, G.; Glatzel, P.; Romani, A.; Miliani, C. |
|
| |
Title |
Damages induced by synchrotron radiation-based X-ray microanalysis in chrome yellow paints and related Cr-compounds : assessment, quantification, and mitigation strategies |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Analytical Chemistry |
Abbreviated Journal |
Anal Chem |
|
| |
Volume |
92 |
Issue |
20 |
Pages |
14164-14173 |
|
| |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
|
| |
Abstract |
Synchrotron radiation (SR)-based X-ray methods are powerful analytical tools for several purposes. They are widely used to probe the degradation mechanisms of inorganic artists' pigments in paintings, including chrome yellows (PbCr1-xSxO4; 0 <= x <= 0.8), a class of compounds often found in Van Gogh masterpieces. However, the high intensity and brightness of SR beams raise important issues regarding the potential damage inflicted on the analyzed samples. A thorough knowledge of the SR X-ray sensitivity of each class of pigment in the painting matrix is therefore required to find analytical strategies that seek to minimize the damage for preserving the integrity of the analyzed samples and to avoid data misinterpretation. Here, we employ a combination of Cr K-edge X-ray absorption near-edge structure spectroscopy, Cr-K-beta X-ray emission spectroscopy, and X-ray diffraction to monitor and quantify the effects of SR X-rays on the stability of chrome yellows and related Cr compounds and to define mitigation strategies. We found that the SR X-ray beam exposure induces changes in the oxidation state and local coordination environment of Cr ions and leads to a loss of the compound's crystalline structure. The extent of X-ray damage depends on some intrinsic properties of the samples (chemical composition of the pigment and the presence/absence and nature of the binder). It can be minimized by optimizing the overall fluence/dose released to the samples and by working in vacuum and under cryogenic conditions. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000584418100072 |
Publication Date |
2020-09-21 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
7.4 |
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 7.4; 2020 IF: 6.32 |
|
| |
Call Number |
UA @ admin @ c:irua:174363 |
Serial |
7754 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Monico, L.; d'Acapito, F.; Cotte, M.; Janssens, K.; Romani, A.; Ricci, G.; Miliani, C.; Cartechini, L. |
|
| |
Title |
Total electron yield (TEY) detection mode Cr K-edge XANES spectroscopy as a direct method to probe the composition of the surface of darkened chrome yellow (PbCr1-xSxO4) and potassium chromate paints |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
Nuclear instruments and methods in physics research: B: beam interactions with materials and atoms |
Abbreviated Journal |
|
|
| |
Volume |
539 |
Issue |
|
Pages |
141-147 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Antwerp X-ray Imaging and Spectroscopy (AXIS) |
|
| |
Abstract |
The darkening of chromate-pigments, including chrome yellows (PbCr1-xSxO4), is a surface phenomenon affecting late 19th-early 20th c. paintings, such as those by Van Gogh. Exploring analytical strategies that contribute to a deep understanding of darkening is therefore significant for the long-term conservation of unique masterpieces. Here, we examined the capabilities of Cr K-edge XANES spectroscopy collected at the same time in X-ray fluorescence yield (XFY) and total electron yield (TEY) detection modes to selectively study the surface composition of darkened oil paint mock-ups composed of chrome yellow (PbCr0.2S0.8O4) or potassium chromate. By discussing advantages and drawbacks in using XFY/TEY modes in relation to XFY & mu;-XANES analysis from sectioned samples, we aim at assessing if TEY-XANES spectroscopy: (i) is a selective surface method to determine the abundance of different Cr-species from paint fragments; (ii) can contribute to optimize the analytical strategy by limiting time consuming sample preparation procedures; (iii) can decrease the probability of radiation damage. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
001041485400001 |
Publication Date |
2023-04-10 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0168-583x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
1.3 |
Times cited |
|
Open Access |
OpenAccess |
|
| |
Notes |
|
Approved |
Most recent IF: 1.3; 2023 IF: 1.109 |
|
| |
Call Number |
UA @ admin @ c:irua:198427 |
Serial |
8944 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Monico, L.; Hendriks, E.; Geldof, M.; Miliani, C.; Janssens, K.; Brunetti, B.G.; Cotte, M.; Vanmeert, F.; Chieli, A.; Van der Snickt, G.; Romani, A.; Melo, M.J. |
|
| |
Title |
Chemical alteration and colour changes in the Amsterdam sunflowers |
Type |
H1 Book chapter |
| |
Year |
2019 |
Publication |
|
Abbreviated Journal |
|
|
| |
Volume |
|
Issue |
|
Pages |
125-158
T2 - Van Gogh’s Sunflowers illuminated – a |
|
| |
Keywords |
H1 Book chapter; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES) |
|
| |
Abstract |
This chapter provides a description of colour changes in the Amsterdam Sunflowers due to chemical alteration of pigments, with a focus on geranium lakes and chrome yellows. The brilliant and forceful colours of these and other late nineteenth-century synthetic materials offered artists such as Vincent van Gogh new means of artistic expression that exploited a range of contrasting hues and tints. However, geranium lakes have a strong tendency to fade and chrome yellows to darken under the influence of light. Van Gogh, like other artists of his day, was aware of this drawback, yet he continued to favour the use of both pigments up until his death in July 1890 due to the unparalleled effects they gave. In April 1888, Vincent wrote to his brother Theo: Van Gogh's use of unstable colours opens a series of questions regarding the extent to which colour change affects the way his paintings look today, as discussed here in relation to the Amsterdam Sunflowers. Furthermore, given the frequency with which geranium lakes and chrome yellows occur in Van Gogh's paintings of the period 1888–90 and the predominance of chrome yellows in Sunflowers, it becomes important to understand the factors that can drive these processes of deterioration in order to develop appropriate strategies for conserving the artist's works. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
|
Publication Date |
2020-11-25 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
978-94-6372-532-3 |
Additional Links |
UA library record |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
no |
|
| |
Call Number |
UA @ admin @ c:irua:190779 |
Serial |
7640 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Monico, L.; Janssens, K.; Alfeld, M.; Cotte, M.; Vanmeert, F.; Ryan, C.G.; Falkenberg, G.; Howard, D.L.; Brunetti, B.G.; Miliani, C. |
|
| |
Title |
Full spectral XANES imaging using the Maia detector array as a new tool for the study of the alteration process of chrome yellow pigments in paintings by Vincent van Gogh |
Type |
A1 Journal article |
| |
Year |
2015 |
Publication |
Journal of analytical atomic spectrometry |
Abbreviated Journal |
J Anal Atom Spectrom |
|
| |
Volume |
30 |
Issue |
3 |
Pages |
613-626 |
|
| |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
|
| |
Abstract |
A combination of synchrotron radiation (SR) micro X-ray fluorescence (m-XRF) and XRF mode X-ray absorption near edge structure (XANES) measurements at the Cr K-edge already allowed us to establish that the photo-reduction of chromates to Cr(III) compounds is the cause of darkening of chrome yellow pigments (PbCr1-xSxO4, 0 <= x <= 0.8) in a number of paintings by Vincent van Gogh and in corresponding artificially aged paint models. A silicon drift detector (SDD) was employed to record the Cr-K XRF radiation in these X-ray micro beam-based measurements. However, in view of the limited count rate capabilities and collection solid angle of a single device, m-XRF and m-XANES employing single element SDDs (or similar) are primarily suited for collection of spectral data from individual points. Additionally, collection of XRF maps via point-by-point scanning with relatively long dwell times per point is possible but is usually confined to small areas. The development of the 384 silicon-diode array Maia XRF detector has provided valuable solutions in terms of data acquisition rate, allowing for full spectral (FS) XANES imaging in XRF mode, i.e., where spectroscopic information is available at each pixel in the scanned map. In this paper, the possibilities of SR Cr K-edge FS-XANES imaging in XRF mode using the Maia detector are examined as a new data collection strategy to study the speciation and distribution of alteration products of lead chromate-based pigments in painting materials. The results collected from two micro-samples taken from two Van Gogh paintings and an aged paint model show the possibility to perform FS-XANES imaging in practical time frames (from several minutes to a few hours) by scanning regions of sample sizes of the same order (more than 500 mm). The sensitivity and capabilities of FS-XANES imaging in providing representative chemical speciation information at the microscale (spatial resolution from similar to 2 to 0.6 mm) over the entire scanned area are demonstrated by the identification of Cr(OH) 3, Cr(III) sulfates and/or Cr(III) organometallic compounds in the corresponding phase maps, as alteration products. Comparable Cr-speciation results were obtained by performing equivalent higher spatial resolution SR m-XRF/single-point m-XANES analysis using a more conventional SDD from smaller regions of interest of each sample. Thus, large-area XRF mode FS-XANES imaging (Maia detector) is here proposed as a valuable and complementary data collection strategy in relation to “ zoomed-in” high-resolution m-XRF mapping and single-point m-XANES analysis (SDD). |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000350650800006 |
Publication Date |
2014-12-17 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0267-9477 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.379 |
Times cited |
28 |
Open Access |
|
|
| |
Notes |
; This research was supported by the Interuniversity Attraction Poles Programme – Belgian Science Policy (S2-ART project S4DA), GOA “SOLARPAINT” (Research Fund University of Antwerp, Belgium) and FWO (Brussels, Belgium) project no. G.0C12.13, G.0704.08 and G.01769.09. Support from the Italian projects PRIN (SICH Sustainability in Cultural Heritage: from diagnosis to the development of innovative system for consolidation, cleaning and protection) and PON (ITACHA Italian advanced technologies for cultural heritage applications) is also acknowledged. For the grants received thanks are expressed to ESRF (experiments EC-799, EC-1051) and DESY (experiment H-20000043). Part of this research was undertaken at the XFM beamline at the Australian Synchrotron, Victoria, Australia (experiment M4604). LM acknowledges the CNR for the financial support received in the framework of the Short Term Mobility Programme 2013. Thanks are expressed to Ella Hendriks (Van Gogh Museum, Amsterdam), Muriel Geldof (Cultural Heritage Agency of The Netherlands) and Margje Leeuwestein (Kroller-Muller Museum, Otterlo) for selecting and sharing the information on the cross-section taken from the paintings The Bedroom and Falling Leaves (Les Alyscamps). All the staff of the Van Gogh Museum and the Kroller-Muller Museum are acknowledged for their agreeable cooperation. ; |
Approved |
Most recent IF: 3.379; 2015 IF: 3.466 |
|
| |
Call Number |
UA @ admin @ c:irua:125475 |
Serial |
5628 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Monico, L.; Janssens, K.; Cotte, M.; Romani, A.; Sorace, L.; Grazia, C.; Brunetti, B.G.; Miliani, C. |
|
| |
Title |
Synchrotron-based X-ray spectromicroscopy and electron paramagnetic resonance spectroscopy to investigate the redox properties of lead chromate pigments under the effect of visible light |
Type |
A1 Journal article |
| |
Year |
2015 |
Publication |
Journal of analytical atomic spectrometry |
Abbreviated Journal |
J Anal Atom Spectrom |
|
| |
Volume |
30 |
Issue |
7 |
Pages |
1500-1510 |
|
| |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
|
| |
Abstract |
Light-induced redox processes have been established as the cause of the chromatic alterations of a number of artists' pigments used from the 15th to the 20th century. Despite the fact that a general comprehension of the mechanisms has been provided through the characterization of photo-degraded compounds, both exhaustive information on the wavelength-dependence of the alteration process of the pigments and experimental evidence in how visible light may influence the formation pathways of specific secondary compounds are still lacking. Establishing an analytical protocol for the study of wavelength-dependence of pigments on photo-redox pathways is relevant for the safe illumination of paintings, especially in view of the possible use of spectrally tunable light sources such as white light emitting diodes (WLEDs). In this work, we propose an integrated approach based on a combination of diffuse reflectance UV-visible, synchrotron radiation (SR)-based micro X-ray fluorescence (m-XRF)/X-ray absorption near edge structure (m-XANES) and electron paramagnetic resonance (EPR) spectroscopies to study the photo-redox process of Cr(VI) -> Cr(III) for lead chromate yellows (PbCr1-xSxO4, 0 <= x <= 0.8) under exposure to different monochromatic light. In view of the thin (3-5 mm) alteration layer that is formed at the paint surface after light exposure, SR-based Cr K-edge mu-XANES/mu-XRF analysis was employed to obtain information on the abundance, nature and distribution of the alteration of Cr(III)-compounds at the micrometricscale level. On the other hand, EPR spectroscopy was used as a complementary tool to the SR-based X-ray methods due to its sensitivity for revealing species containing one or more unpaired electrons and for distinguishing different coordination geometries of paramagnetic centers, such as Cr(V)-species. Semi-quantitative indications about the darkening of the paint surface were obtained by UV-Vis spectroscopy. An abundance of reduced Cr down to around 50% was detected at the aged surface of chrome yellow paints. The reduction process was favored not only by wavelengths shorter than 460 nm (i.e., where the pigment shows its maximum absorption) but also by light in the 490-530 nm range. The first evidence of the presence of Cr(V)-intermediates in the Cr(VI) -> Cr(III) reduction reaction allowed the risks of inducing photo-degradation of the 490-530 nm wavelength range to be explained. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000356971900004 |
Publication Date |
2015-04-15 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0267-9477 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.379 |
Times cited |
17 |
Open Access |
|
|
| |
Notes |
; This research was supported by the Italian projects PRIN-(SICH) and PON- (ITACHA) and by Belgian Science Policy project S2-ART (BELSPO S4DA), the GOA “SOLARPAINT” (Research Fund Antwerp University, Belgium) and FWO (Brussels, Belgium) projects no. G.0C12.13, G.0704.08 and G.01769.09. ESRF is acknowledged for the grants received (experiments HG18 and HG26). L.S. and L.M. acknowledge the financial support of Ente-CRF and CNR-Short Term Mobility Programme 2013, respectively. ; |
Approved |
Most recent IF: 3.379; 2015 IF: 3.466 |
|
| |
Call Number |
UA @ admin @ c:irua:127059 |
Serial |
5862 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Monico, L.; Janssens, K.; Cotte, M.; Sorace, L.; Vanmeert, F.; Brunetti, B.G.; Miliani, C. |
|
| |
Title |
Chromium speciation methods and infrared spectroscopy for studying the chemical reactivity of lead chromate-based pigments in oil medium |
Type |
A1 Journal article |
| |
Year |
2016 |
Publication |
Microchemical journal
T2 – TECHNART Conference, APR 27-30, 2015, Catania, ITALY |
Abbreviated Journal |
Microchem J |
|
| |
Volume |
124 |
Issue |
|
Pages |
272-282 |
|
| |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
|
| |
Abstract |
Environmental factors, such as light, humidity and temperature are triggering agents for the alteration of organic and/or inorganic constituents of oil paintings. The oxidation of the organic material is favored by increasing of relative humidity and temperature, whereas processes involving changes of the oxidation states of a number of inorganic pigments (e.g., vermilion, cadmium yellows, zinc yellows, chrome yellows) are mainly activated by light-exposure. In view of the optimization of the long-term conservation and restoration strategies of paintings it is of relevant interest to establish the consequences of thermal parameters (temperature and relative humidity) on the chemical/photochemical-reactivity and the nature of the alteration products of light sensitive-pigments in oil medium. To this aim here we propose a multi-method analytical approach based on the combination of diffuse reflectance UV-Vis, FTIR, synchrotron radiation (SR)-based micro X-ray fluorescence (mu-XRF)/micro-X-ray absorption neat edge structure ()CANES) and electron paramagnetic resonance (EPR) spectroscopies for studying the effects of different relative humidity conditions before and after light exposure on the reactivity of a series of lead chromate-based pigments [such as PbCrO4 center dot PbO (monoclinic), PbCrO4 (monoclinic) and PbCr0.2S0.8O4 (orthorhombic)] in an oil medium. The investigation of paint models was also compared to that of a late 19th century historical orthorhombic PbCr0.4S0.6O4 oil paint. Diffuse reflectance UV-Vis and FTIR spectroscopies were used to obtain information associated with chromatic changes and the formation of organo-metal degradation products at the paint surface. SR-based Cr K-edge mu-XANES/mu-XRF mapping analysis and EPR spectroscopy were employed in a complementary fashion to determine the amount, nature and distribution of Cr(III) and Cr(V)-based alteration compounds within the paints with micrometric spatial resolution. Under the employed thermal aging conditions, lead(II)-carboxylates and reduced Cr-compounds (in abundance of up to about 35% at the surface) have been identified in the lead chromate-based paints. The tendency of chromates to become reduced increased with increasing moisture levels and was favored for the orthorhombic PbCr0.2S0.8O4 compounds. The redox process gave rise to the formation of Cr(V)-species in relative amount much higher than that was formed in the equivalent paint which was exposed only to light. After light-exposure of the thermally aged paints, compounds ascribable to the oxidation of the organic binder were detected for all the types of pigments. Nevertheless, the previous thermal treatment increased the tendency toward photo-reduction of only the PbCr0.2S0.8O4 pigment. For this light-sensitive compound, the thickness variation of the reduced Cr-rich (ca. 70%) photo-alteration layer with moisture levels could be ascribed to a surface passivation phenomenon that had already occurred before photochemical aging. (C) 2015 Elsevier B.V. All rights reserved. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000367755600042 |
Publication Date |
2015-09-12 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0026-265x; 0026-265x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.034 |
Times cited |
23 |
Open Access |
|
|
| |
Notes |
; ; |
Approved |
Most recent IF: 3.034 |
|
| |
Call Number |
UA @ admin @ c:irua:131099 |
Serial |
5519 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Monico, L.; Janssens, K.; Hendriks, E.; Brunetti, B.G.; Miliani, C. |
|
| |
Title |
Raman study of different crystalline forms of PbCrO4 and PbCr1-xSxO4 solid solutions for the noninvasive identification of chrome yellows in paintings : a focus on works by Vincent van Gogh |
Type |
A1 Journal article |
| |
Year |
2014 |
Publication |
Journal of Raman spectroscopy |
Abbreviated Journal |
J Raman Spectrosc |
|
| |
Volume |
45 |
Issue |
11-12 |
Pages |
1034-1045 |
|
| |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
|
| |
Abstract |
Chrome yellows, a class of pigments frequently used by painters of the Impressionism and Post-impressionism period, are known for their different chemical stability; the latter depends on the chemical composition (PbCrO4, PbCr1-xSxO4) and crystalline structure (monoclinic or orthorhombic) of the material. The possibility to distinguish among different forms of this pigment is therefore relevant in order to extend knowledge on the corresponding degradation process that is observed on several original paintings. For this purpose, three paintings conserved at the Van Gogh Museum (Amsterdam) were analyzed using noninvasive Raman spectroscopy, while equivalent investigations employing bench-top instrumentation were performed to obtain information from micro-samples originating from these works of art. In each painting, the chrome yellow was identified either as monoclinic PbCrO4 or in the form of monoclinic PbCr1-xSxO4 (x<0.25) or S-rich orthorhombic PbCr1-xSxO4 (x similar to 0.5). Our ability to make this fairly subtle distinction is based on a Raman study of several oil paint model samples made up of monoclinic and/or orthorhombic crystalline forms of PbCrO4 and PbCr1-xSxO4 (0.1x0.8). These paints were studied using several excitation wavelengths (namely 785.0, 532.0, 514.5, and 488nm). Because of the absence of the resonance Raman effect, which strongly enhances the chromate symmetric stretching band, and the absence of any laser-induced photodecomposition, it is advantageous to acquire data at 785.0nm. The band-shape and the position of the chromate bending modes proved to be more sensitive to the solid solution composition and crystalline structure than the stretching modes and can be used as distinctive spectral markers to discriminate among the different chrome yellow forms that are present. Copyright (c) 2014 John Wiley & Sons, Ltd. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000346912700008 |
Publication Date |
2014-07-17 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0377-0486 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.969 |
Times cited |
34 |
Open Access |
|
|
| |
Notes |
; This research was supported by Interuniversity Attraction Poles Programme – Belgian Science Policy (S2-ART project S4DA) and also presents results from GOA 'XANES meets ELNES' (Research Fund University of Antwerp, Belgium), FWO (Brussels, Belgium) projects no. G.0704.08 and G.01769.09. Support from the Italian projects PRIN (SICH Sustainability in Cultural Heritage: from diagnosis to the development of innovative system for consolidation, cleaning and protection) and PON (ITACHA Italian advanced technologies for cultural heritage applications) is also acknowledged. The analysis of the paintings Sunflowers gone to seed, Bank of the Seine, and Portrait of Gauguin was performed within the mobile laboratory access activity of the FP7 programme CHARISMA supported by EC (Grant Agreement 228330). LM acknowledges the Italian National Research Council (CNR) for the financial support in the framework of the Short Term Mobility Programme 2013. Thanks are expressed to Muriel Geldof, Cultural Heritage Agency of The Netherlands, for selecting and sharing the information on the cross-sections and to the staff of the Van Gogh Museum for the agreeable cooperation. ; |
Approved |
Most recent IF: 2.969; 2014 IF: 2.671 |
|
| |
Call Number |
UA @ admin @ c:irua:122841 |
Serial |
5798 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Monico, L.; Janssens, K.; Hendriks, E.; Vanmeert, F.; van der Snickt, G.; Cotte, M.; Falkenberg, G.; Brunetti, B.G.; Miliani, C. |
|
| |
Title |
Evidence for degradation of the chrome yellows in Van Gogh's sunflowers : a study using noninvasive in situ methods and synchrotron-radiation-based x-ray techniques |
Type |
A1 Journal article |
| |
Year |
2015 |
Publication |
Angewandte Chemie: international edition in English |
Abbreviated Journal |
Angew Chem Int Edit |
|
| |
Volume |
54 |
Issue |
47 |
Pages |
13923-13927 |
|
| |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
|
| |
Abstract |
This paper presents firm evidence for the chemical alteration of chrome yellow pigments in Van Gogh's Sunflowers (Van Gogh Museum, Amsterdam). Noninvasive in situ spectroscopic analysis at several spots on the painting, combined with synchrotron-radiation-based X-ray investigations of two microsamples, revealed the presence of different types of chrome yellow used by Van Gogh, including the lightfast PbCrO4 and the sulfur-rich PbCr1-xSxO4 (x approximate to 0.5) variety that is known for its high propensity to undergo photoinduced reduction. The products of this degradation process, i.e., Cr-III compounds, were found at the interface between the paint and the varnish. Selected locations of the painting with the highest risk of color modification by chemical deterioration of chrome yellow are identified, thus calling for careful monitoring in the future. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000367722500009 |
Publication Date |
2015-10-20 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1433-7851; 0570-0833 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
11.994 |
Times cited |
24 |
Open Access |
|
|
| |
Notes |
; We acknowledge financial support from the Italian MIUR project SICH-PRIN (2010329WPF_001) and BELSPO (Brussels) Project S2-ART (SD04A), GOA “SOLARPAINT” (Research Fund Antwerp University, BOF-2015), and FWO (Brussels) projects G.0C12.13, G.0704.08, G.01769.09. We thank ESRF (EC-1051, HG-26) and DESY (I-20120312 EC) for beamtime grants received. Noninvasive analysis of Sunflowers were supported by the EU FP7 programme CHARISMA (Grant 228330) and the Fund Inbev-Baillet Latour (Brussels). L.M. acknowledges financial support from the CNR Short Term Mobility Programme-2013. We thank Muriel Geldof, Luc Megens, Suzan de Groot (The Netherlands Cultural Heritage Agency, RCE), Chiara Grazia, David Buti (CNR-ISTM and SMAArt Centre), and the staff of the Van Gogh Museum for their collaboration. ; |
Approved |
Most recent IF: 11.994; 2015 IF: 11.261 |
|
| |
Call Number |
UA @ admin @ c:irua:131110 |
Serial |
5617 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Monico, L.; Janssens, K.; Miliani, C.; van der Snickt, G.; Brunetti, B.G.; Guidi, M.C.; Radepont, M.; Cotte, M. |
|
| |
Title |
Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of spectromicroscopic methods : 4 : artificial aging of model samples of co-precipitates of lead chromate and lead sulfate |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
|
| |
Volume |
85 |
Issue |
2 |
Pages |
860-867 |
|
| |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
|
| |
Abstract |
Previous investigations about the darkening of chrome yellow pigments revealed that this form of alteration is attributable to a reduction of the original Cr(VI) to Cr(III), and that the presence of sulfur-containing compounds, most often sulfates, plays a key role during this process. We recently demonstrated that different crystal forms of chrome yellow pigments (PbCrO4 and PbCr1xSxO4) are present in paintings by Vincent van Gogh. In the present work, we show how both the chemical composition and the crystalline structure of lead chromate-based pigments influence their stability. For this purpose, oil model samples made with in-house synthesized powders of PbCrO4 and PbCr1xSxO4 were artificially aged and characterized. We observed a profound darkening only for those paint models made with PbCr1xSxO4, rich in SO42 (x ≥ 0.4), and orthorhombic phases (>30 wt %). Cr and S K-edge micro X-ray absorption near edge structure investigations revealed in an unequivocal manner the formation of up to about 60% of Cr(III)-species in the outer layer of the most altered samples; conversely, independent of the paint models chemical composition, no change in the S-oxidation state was observed. Analyses employing UVvisible diffuse reflectance and Fourier transform infrared spectroscopy were performed on unaged and aged model samples in order to obtain additional information on the physicochemical changes induced by the aging treatment. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000313668400032 |
Publication Date |
2012-10-10 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
6.32 |
Times cited |
49 |
Open Access |
|
|
| |
Notes |
; This research was supported by grants from ESRF (experiment EC-799), the Interuniversity Attraction Poles Programme-Belgian Science Policy (IUAP VI/16), and the BELSPO-SDD S2-ART (SD/RI/04) project. The text also presents results from GOA “XANES meets ELNES” (Research Fund University of Antwerp, Belgium) and FWO (Brussels, Belgium) projects G.0704.08 and G.01769.09. The EU FP7 programme CHARISMA (Grant Agreement 228330) and MIUR (PRIN08, Materiali e sistemi innovativi per la conservazione dell'arte contemporanea 2008 FFXXN9) are also acknowledged. ; |
Approved |
Most recent IF: 6.32; 2013 IF: 5.825 |
|
| |
Call Number |
UA @ admin @ c:irua:110471 |
Serial |
5569 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Monico, L.; Janssens, K.; Vanmeert, F.; Cotte, M.; Brunetti, B.G.; van der Snickt, G.; Leeuwestein, M.; Plisson, J.S.; Menu, M.; Miliani, C. |
|
| |
Title |
Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of spectromicroscopic methods : part 5 : effects of nonoriginal surface coatings into the nature and distribution of chromium and sulfur species in chrome yellow paints |
Type |
A1 Journal article |
| |
Year |
2014 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
|
| |
Volume |
86 |
Issue |
21 |
Pages |
10804-10811 |
|
| |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
|
| |
Abstract |
The darkening of lead chromate yellow pigments, caused by a reduction of the chromate ions to Cr(III) compounds, is known to affect the appearance of several paintings by Vincent van Gogh. In previous papers of this series, we demonstrated that the darkening is activated by light and depends on the chemical composition and crystalline structure of the pigments. In this work, the results of Part 2 are extended and complemented with a new study aimed at deepening the knowledge of the nature and distribution of Cr and S species at the interface between the chrome yellow paint and the nonoriginal coating layer. For this purpose, three microsamples from two varnished paintings by Van Gogh and a waxed low relief by Gauguin (all originally uncoated) have been examined. Because nonoriginal coatings are often present in artwork by Van Gogh and contemporaries, the understanding of whether or not their application has influenced the morphological and/or physicochemical properties of the chrome yellow paint underneath is relevant in view of the conservation of these masterpieces. In all the samples studied, microscopic X-ray fluorescence (mu-XRF) and X-ray absorption near edge structure (mu-XANES) investigations showed that Cr(III)-based alteration products are present in the form of grains inside the coating (generally enriched of S species) and also homogeneously widespread at the paint surface. The distribution of Cr(III) species may be explained by the mechanical friction caused by the coating application by brush that picked up and redistributed the superficial Cr compounds, likely already present in the reduced state as result of the photodegradation process. The analysis of the XANES profiles allowed us to obtain new insights into the nature of the Cr(III) alteration products, that were identified as sulfate-, oxide-, organo-metal-, and chloride-based compounds. Building upon the knowledge acquired through the examination of original paint samples and from the investigation of aged model paints in the last Part 4 paper, in this study we aim to characterize a possible relation between the chemical composition of the coating and the chrome yellow degradation pathways by studying photochemically aged model samples covered with a dammar varnish contaminated with sulfide and sulfate salts. Cr speciation results did not show any evidence of the active role of the varnish and added S species on the reduction process of chrome yellows. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000344510200043 |
Publication Date |
2014-10-10 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
6.32 |
Times cited |
25 |
Open Access |
|
|
| |
Notes |
; This research was supported by the Italian projects PRIN (SICH) and PON (ITACHA). The text also presents results from Interuniversity Attraction Poles Programme Belgian Science Policy (S2-ART project S4DA), GOA “XANES meets ELNES” (Research Fund University of Antwerp, Belgium) and FWO (Brussels, Belgium) projects no. G.0704.08 and G.01769.09. ESRF is acknowledged for the grants received (experiments EC-799 and EC-1051). L.M. acknowledges the CNR for the financial support received in the framework of the Short Term Mobility Programme 2013. Thanks are expressed to Ella Hendriks (Van Gogh Museum, Amsterdam) and Muriel Geldof (Cultural Heritage Agency of The Netherlands) for selecting and sharing the information on the cross-section taken from Bank of the Seine. All the staff of the Van Gogh Museum, the Kroller-Muller Museum, and the Musee d'Orsay are acknowledged for the agreeable cooperation. ; |
Approved |
Most recent IF: 6.32; 2014 IF: 5.636 |
|
| |
Call Number |
UA @ admin @ c:irua:122100 |
Serial |
5570 |
|
| Permanent link to this record |
