“3Y-TZP ceramics with improved hydrothermal degradation resistance and fracture toughness”. Zhang F, Vanmeensel K, Inokoshi M, Batuk M, Hadermann J, Van Meerbeek B, Naert I, Vleugels J, Journal of the European Ceramic Society 34, 2453 (2014). http://doi.org/10.1016/j.jeurceramsoc.2014.02.026
Abstract: Different factors such as the way of incorporating the Y2O3 stabilizer, alumina addition and sintering temperature were assessed with the goal to improve the low temperature degradation (LTD) resistance of 3Y-TZP without compromising on the mechanical properties. The degradation of hydrothermally treated specimens was studied by X-ray diffraction, micro-Raman spectroscopy and scanning electron microscopy. Decreasing the sintering temperature decreased the LTD susceptibility of 3Y-TZPs but did not allow to obtain a LTD resistant 3Y-TZP with optimized mechanical properties. Alumina addition along with the use of Y2O3 stabilizer coated starting powder allowed to combine both an excellent toughness and LTD resistance, as compared to alumina-free and stabilizer co-precipitated powder based equivalents. Transmission electron microscopy revealed that the improved LTD resistance could be attributed to the segregation of Al3+ at the grain boundary and the heterogeneously distributed Y3+ stabilizer.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 48
DOI: 10.1016/j.jeurceramsoc.2014.02.026
|
“3D imaging of nanomaterials by discrete tomography”. Batenburg KJ, Bals S, Sijbers J, Kübel C, Midgley PA, Hernandez JC, Kaiser U, Encina ER, Coronado EA, Van Tendeloo G, Ultramicroscopy 109, 730 (2009). http://doi.org/10.1016/j.ultramic.2009.01.009
Abstract: The field of discrete tomography focuses on the reconstruction of samples that consist of only a few different materials. Ideally, a three-dimensional (3D) reconstruction of such a sample should contain only one grey level for each of the compositions in the sample. By exploiting this property in the reconstruction algorithm, either the quality of the reconstruction can be improved significantly, or the number of required projection images can be reduced. The discrete reconstruction typically contains fewer artifacts and does not have to be segmented, as it already contains one grey level for each composition. Recently, a new algorithm, called discrete algebraic reconstruction technique (DART), has been proposed that can be used effectively on experimental electron tomography datasets. In this paper, we propose discrete tomography as a general reconstruction method for electron tomography in materials science. We describe the basic principles of DART and show that it can be applied successfully to three different types of samples, consisting of embedded ErSi2 nanocrystals, a carbon nanotube grown from a catalyst particle and a single gold nanoparticle, respectively.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Impact Factor: 2.843
Times cited: 220
DOI: 10.1016/j.ultramic.2009.01.009
|
“The (3 + 2)D structure of oxygen deficient LaSrCuO3.52”. Hadermann J, Pérez O, Créon N, Michel C, Hervieu M, Journal of materials chemistry 17, 2344 (2007). http://doi.org/10.1039/b701449j
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Times cited: 7
DOI: 10.1039/b701449j
|
“3D reconstruction of Ni4Ti3 precipitates in a Ni51Ti49 alloy in a FIB/SEM dual-beam system”. Cao S, Tirry W, van den Broek W, Schryvers D, Materials science forum 583, 277 (2008). http://doi.org/10.4028/www.scientific.net/MSF.583.277
Abstract: Ni4Ti3 precipitates play an important role in the shape memory and superelastic behaviour of thermo-mechanically treated Ni-Ti material. The 3D morphology and distribution of such precipitates with lenticular shape and rhombohedral atomic structure in the austenitic B2 matrix of a binary Ni-rich Ni-Ti alloy has been elucidated via a slice view procedure in a Dual-Beam FIB/SEM system. With the sequence of cross-section SE images obtained from the SEM, a 3D reconstruction has been achieved after proper alignment and image processing, from which both qualitative and quantitative analysis can be performed. Careful imaging is needed to ensure that all variants of the precipitates are observed with equal probability, regardless sample orientation. Moreover, due to the weak contrast of the precipitates, proper imaging conditions need to be selected to allow for semi-automated image treatment. Finally, a volume ratio of 10.2% for the Ni4Ti3 precipitates could be calculated, summed over all variants, which yields a net composition of Ni50.36Ti49.64 for the matrix, leading to an increase of 113 degrees for the martensitic start temperature Ms. Also, the expected relative orientation of the different variants of the precipitates could be confirmed. In the near future, other quantitative measures on the distribution of the precipitates can be expected.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
DOI: 10.4028/www.scientific.net/MSF.583.277
|
“30-band k\cdot p model of electron and hole states in silicon quantum wells”. Čukarić, NA, Tadić, MZ, Partoens B, Peeters FM, Physical review : B : condensed matter and materials physics 88, 205306 (2013). http://doi.org/10.1103/PhysRevB.88.205306
Abstract: We modeled the electron and hole states in Si/SiO2 quantum wells within a basis of standing waves using the 30-band k . p theory. The hard-wall confinement potential is assumed, and the influence of the peculiar band structure of bulk silicon on the quantum-well sub-bands is explored. Numerous spurious solutions in the conduction-band and valence-band energy spectra are found and are identified to be of two types: (1) spurious states which have large contributions of the bulk solutions with large wave vectors (the high-k spurious solutions) and (2) states which originate mainly from the spurious valley outside the Brillouin zone (the extravalley spurious solutions). An algorithm to remove all those nonphysical solutions from the electron and hole energy spectra is proposed. Furthermore, slow and oscillatory convergence of the hole energy levels with the number of basis functions is found and is explained by the peculiar band mixing and the confinement in the considered quantum well. We discovered that assuming the hard-wall potential leads to numerical instability of the hole states computation. Nonetheless, allowing the envelope functions to exponentially decay in a barrier of finite height is found to improve the accuracy of the computed hole states.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 10
DOI: 10.1103/PhysRevB.88.205306
|
“90°, Rotation of orbital stripes in bilayer manganite PrCa2Mn2O7 studied by in situ transmission electron microscopy”. He ZB, Deng G, Tian H, Xu Q, Van Tendeloo G, Journal of solid state chemistry 200, 287 (2013). http://doi.org/10.1016/j.jssc.2013.01.051
Abstract: We present an in situ transmission electron microscopy study on the half-doped bilayer manganite PrCa2Mn2O7 to reveal the rotation process of the orbital stripes. Between the reported initial and final ordering phases, we identified an intermediate state with two sets of satellite spots to bridge the 90° rotation of the orbital stripes. Furthermore, we determined that the rotation of the orbital stripes does not always occur. Some restricted conditions for the orbital rotation to occur were found and reasons are discussed.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 5
DOI: 10.1016/j.jssc.2013.01.051
|
“A 94K Hg-based superconductor with a “1212&rdquo, structure HG0.5Bi0.5Sr2Ca1-xRxCu2O6+\delta (R=ND,Y,Pr)”. Pelloquin D, Hervieu M, Michel C, Van Tendeloo G, Maignan A, Raveau B, Physica: C : superconductivity 216, 257 (1993)
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 0.942
Times cited: 62
|
“{110}-Layered B-cation ordering in the anion-deficient perovskite Pb2.4Ba2.6Fe2Sc2TiO13 with the crystallographic shear structure”. Tyablikov OA, Batuk D, Tsirlin AA, Batuk M, Verchenko VY, Filimonov DS, Pokholok KV, Sheptyakov DV, Rozova MG, Hadermann J, Antipov EV, Abakumov AM;, Journal of the Chemical Society : Dalton transactions 44, 10753 (2015). http://doi.org/10.1039/c4dt03867c
Abstract: A novel anion-deficient perovskite-based compound, Pb2.4Ba2.6Fe2Sc2TiO13, was synthesized via the citrate-based route. This compound is an n = 5 member of the A(n)B(n)O(3n-2) homologous series with unit-cell parameters related to the perovskite subcell a(p) approximate to 4.0 angstrom as a(p)root 2 x a(p) x 5a(p)root 2. The crystal structure of Pb2.4Ba2.6Fe2Sc2TiO13 consists of quasi-2D perovskite blocks with a thickness of three octahedral layers separated by the 1/2[110]((1) over bar 01)(p) crystallographic shear (CS) planes, which are parallel to the {110} plane of the perovskite subcell. The CS planes transform the corner-sharing octahedra into chains of edge-sharing distorted tetragonal pyramids. Using a combination of neutron powder diffraction, Fe-57 Mossbauer spectroscopy and atomic resolution electron energy-loss spectroscopy we demonstrate that the B-cations in Pb2.4Ba2.6Fe2Sc2TiO13 are ordered along the {110} perovskite layers with Fe3+ in distorted tetragonal pyramids along the CS planes, Ti4+ preferentially in the central octahedra of the perovskite blocks and Sc3+ in the outer octahedra of the perovskite blocks. Magnetic susceptibility and Mossbauer spectroscopy indicate a broadened magnetic transition around T-N similar to 45 K and the onset of local magnetic fields at low temperatures. The magnetic order is probably reminiscent of that in other A(n)B(n)O(3n-2) homologues, where G-type AFM order within the perovskite blocks has been observed.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.029
Times cited: 1
DOI: 10.1039/c4dt03867c
|
“A 2a2a3c superstructure in hexagonal Ni1-xS : a study by means of electron-diffraction and HRTEM”. Lioutas CB, Manolikas C, Van Tendeloo G, van Landuyt J, Journal of crystal growth 126, 457 (1993). http://doi.org/10.1016/0022-0248(93)90051-W
Abstract: The high temperature phase of Ni1-xS has the NiAs-type structure. The coexistence of two superstructures, ''3a3a3c'' and ''2a2a3c'' with the basic phase is confirmed by means of electron diffraction. The 2a2a3c superstructure is studied by means of electron diffraction and high resolution electron microscopy. A structure model is proposed based on the periodic insertion of stacking faults in the NiAs-type basic structure and the ordering of vacancies in alternate metal-atom layers. Microtwinning in very narrow slabs is found to be a main feature of the 2a2a3c regions and two defect models are discussed.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.698
Times cited: 4
DOI: 10.1016/0022-0248(93)90051-W
|
“A counterion-catalyzed (S0H+)(X-I+) pathway toward heat- and steam-stable mesostructured silica assembled from amines in acidic conditions”. Cassiers K, van der Voort P, Linssen T, Vansant EF, Lebedev O, van Landuyt J, The journal of physical chemistry : B : condensed matter, materials, surfaces, interfaces and biophysical 107, 3690 (2003). http://doi.org/10.1021/jp026696v
Abstract: An alternative pathway to assemble mesoporous molecular sieve silicas is developed using nonionic alkylamines and N,N-dimethylalkylamines (SO) as structure-directing agents in acidic conditions. The synthesized mesostructures possess wormhole-like frameworks with pore sizes and pore volumes in the range of 20-90 Angstrom and 0.5-1.3 cm(3)/g, respectively. The formation of the mesophase is controlled by a counterion-mediated mechanism of the type (S(0)H(+))(X(-)I(+)), where S(0)H(+) are protonated water molecules that are hydrogen bonded to the lone electron pairs on the amine surfactant headgroups (S(0)H(+)), X(-) is the counteranion originating from the acid, and I(+) are the positively charged (protonated) silicate species. We found that the stronger the ion X(-) is bonded to S(0)H(+), the more it catalyzes the silica condensation into (S(0)H(+))(X(-)I(+)). Br(-) is shown to be a strong binding anion and therefore a fast silica polymerization promoter compared to Cl(-) resulting in the formation of a higher quality mesophase for the Br(-) syntheses. We also showed that the polymerization rate of the silica, dictated by the counterion, controls the morphology of the mesostructures from nonuniform agglomerated blocks in the case of Br(-) syntheses to spherical particles for the Cl(-) syntheses. Next to many benefits such as low temperature, short synthesis time, and the use of inexpensive, nontoxic, and easily extractable amine templates, the developed materials have a remarkable higher thermal and hydrothermal stability compared to hexagonal mesoporous silica, which is also prepared with nonionic amines but formed through the S(0)I(0) mechanism.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 3.177
Times cited: 9
DOI: 10.1021/jp026696v
|
“A novel approach to analyse FTIR spectra of precipitates in boron-doped silicon”. de Gryse O, Vanhellemont J, Clauws P, Lebedev O, van Landuyt J, Simoen E, Claeys C, Physica: B : condensed matter
T2 –, 22nd International Conference on Defects in Semiconductors (ICDS-22), JUL 28-AUG 01, 2003, UNIV AARHUS, AARHUS, DENMARK 340, 1013 (2003). http://doi.org/10.1016/j.physb.2003.09.194
Abstract: Infrared absorption spectra of composite precipitates are analysed with a modified Day-Thorpe algorithm, assuming a precipitated phase consisting of a mixture of two components with known optical properties. Additional constraints are introduced when solving the model equations by using a priori knowledge making the algorithm more reliable. It is shown that this novel approach allows determining both morphology and composition of precipitates. The method is applied to characterise oxide precipitates in boron-doped silicon. The results indicate that for the resistivity range above 60 mOmegacm, the precipitated phase is most probably SiO1.17+/-0.14, while for resistivities below 20 mOmega cm, precipitates consist of a SiO2/B2O3 composite with a large volume fraction of B(2)0(3) (up to 40% for 8 mOmegacm material). (C) 2003 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.386
Times cited: 4
DOI: 10.1016/j.physb.2003.09.194
|
“A-site ordering and stripe phases in manganite films”. Sudheendra L, Moshnyaga V, Lebedev OI, Gehrke K, Belenciuc A, Shapoval O, Van Tendeloo G, Samwer K, Physica: B : condensed matter
T2 –, International Conference on Strongly Correlated Electron Systems (SCES, 2007), MAY 13-18, 2007, Houston, TX 403, 1645 (2008). http://doi.org/10.1016/j.physb.2007.10.332
Abstract: Insulating and metallic stripes above and below the Curie temperature, T-C, respectively, were observed by a high-resolution scanning tunneling microscopy (STM) and/or spectroscopy (STS) in A-site ordered and macroscopically strain free epitaxial La0.75Ca0.25MnO3 film grown on MgO substrate. The “insulating” stripes were found to be incommensurable to the lattice and aligned along (110) direction. Metallic stripes were commensurable with periodicity 2a(p)similar to 0.8 nm and aligned parallel to the crystallographic a/b-axis. Formation of these stripes involves competing charge, orbital, and lattice orders and is an outcome of an overlapping of electron wave functions mediated by the local lattice-strain distribution, existed even in A-site ordered film due to the difference in cation radii of La and Ca. (C) 2007 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.386
DOI: 10.1016/j.physb.2007.10.332
|
“Ab initio based atomic scattering amplitudes and {002} electron structure factors of InxGa1-xAs/GaAs quantum wells”. Titantah JT, Lamoen D, Schowalter M, Rosenauer A, Journal of physics : conference series 209, 012040 (2010). http://doi.org/10.1088/1742-6596/209/1/012040
Abstract: The atomic scattering amplitudes of the various atoms of the systems Ga1−xInxAs, GaAs1−xNx and InAs1−xNx are calculated using the density functional theory (DFT) approach. The scattering amplitudes of N, Ga, As and In in the model systems are compared with the frequently used Doyle and Turner values. Deviation from the latter values is found for small scattering vectors (s<0.3Å−1) and for these scattering vectors dependence on the orientation of the scattering vector and the chemical environment is reported. We suggest a parametrization of these modified scattering amplitudes (MASAs) for small scattering vectors (s<1.0Å−1). The MASAs are exploited within zero pressure classical Metropolis Monte Carlo (MC), finite temperature calculations to investigate the effect of quantum well size on the electron {002} structure factor (SF) of Ga1−xInxAs quantum wells.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
DOI: 10.1088/1742-6596/209/1/012040
|
“Ab initio calculation of the energy-loss near-edge structure of some carbon allotropes: comparison with n-diamond”. Dadsetani M, Titantah JT, Lamoen D, Diamond and related materials 19, 73 (2010). http://doi.org/10.1016/j.diamond.2009.11.004
Abstract: The energy-loss near-edge structure (ELNES) spectra of several carbon allotropes (non-hydrogenated and hydrogenated face-centered cubic (FCC) carbon, rhombohedral carbon, glitter, hexagonite and lonsdaleite) are calculated within the supercell-core-excited density functional theory approach. In particular an experimental ELNES spectrum of new diamond (n-diamond) [Konyashin et al., Diamond Relat. Mater. 10, (2001) 99102] is compared with the ELNES spectra of FCC carbon, rhombohedral carbon and the so-called glitter structure. Our calculations show that the ELNES spectrum considered in that publication cannot be that of FCC carbon.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.561
Times cited: 11
DOI: 10.1016/j.diamond.2009.11.004
|
“Ab initio calculation of the interaction energy in the P2 binding pocket of HIV-1 protease”. Nivesanond K, Peeters A, Lamoen D, van Alsenoy C, International Journal Of Quantum Chemistry 105, 292 (2005). http://doi.org/10.1002/qua.20724
Keywords: A1 Journal article; Electron Microscopy for Materials Science (EMAT);
Impact Factor: 2.92
Times cited: 8
DOI: 10.1002/qua.20724
|
“Ab initio computation of the mean inner Coulomb potential of amorphous carbon structures”. Schowalter M, Titantah JT, Lamoen D, Kruse P, Applied physics letters 86, 112102 (2005). http://doi.org/10.1063/1.1885171
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 15
DOI: 10.1063/1.1885171
|
“Ab initio computation of the mean inner Coulomb potential of technological important semiconductors”. Schowalter M, Rosenauer A, Lamoen D, Kruse P, Gerthsen D, 1007, 233 (2005)
Keywords: A1 Journal article; Electron Microscopy for Materials Science (EMAT);
|
“Ab initio computation of the mean inner Coulomb potential of wurtzite-type semiconductors and gold”. Schowalter M, Rosenauer A, Lamoen D, Kruse P, Gerthsen D, Applied Physics Letters 88, Artn 232108 (2006). http://doi.org/10.1063/1.2210453
Keywords: A1 Journal article; Electron Microscopy for Materials Science (EMAT);
Impact Factor: 3.411
Times cited: 8
DOI: 10.1063/1.2210453
|
“Ab initio spectroscopy and thermochemistry of the BN molecule”. Martin JML, François JP, Gijbels R, Zeitschrift für Physik : D : atoms, molecules and clusters 21, 47 (1991)
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Times cited: 17
|
“Ab initio study of shallow acceptors in bixbyite V2O3”. Sarmadian N, Saniz R, Partoens B, Lamoen D, Journal of applied physics 117, 015703 (2015). http://doi.org/10.1063/1.4905316
Abstract: We present the results of our study on p-type dopability of bixbyite V2O3 using the Heyd, Scuseria, and Ernzerhof hybrid functional (HSE06) within the density functional theory (DFT) formalism. We study vanadium and oxygen vacancies as intrinsic defects and substitutional Mg, Sc, and Y as extrinsic defects. We find that Mg substituting V acts as a shallow acceptor, and that oxygen vacancies are electrically neutral. Hence, we predict Mg-doped V2O3 to be a p-type conductor. Our results also show that vanadium vacancies are relatively shallow, with a binding energy of 0.14 eV, so that they might also lead to p-type conductivity.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 2.068
Times cited: 3
DOI: 10.1063/1.4905316
|
“Ab initio study of the spectroscopy, kinetics, and thermochemistry of the BN2 molecule”. Martin JML, Taylor PR, François JP, Gijbels R, Chemical physics letters 222, 517 (1994). http://doi.org/10.1016/0009-2614(94)00378-5
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.897
Times cited: 14
DOI: 10.1016/0009-2614(94)00378-5
|
“Ab initio study of the spectroscopy, kinetics, and thermochemistry of the C2N and CN2 molecules”. Martin JML, Taylor PR, François JP, Gijbels R, Chemical physics letters 226, 475 (1994). http://doi.org/10.1016/0009-2614(94)00758-6
Abstract: Several structures and electronic states of the C2N and CN2 molecules have been studied using complete active space SCF (CASSCF), multireference configuration interaction (MRCI), and coupled cluster (CCSD(T)) methods. Both molecules are very stable. Our best computed total atomization energies SIGMAD(e) are 288.6 +/- 2 kcal/mol for CN2, and 294.1 +/- 2 kcal/mol for C2N. The CNC and CCN structures for C2N are nearly isoenergetic. CNN(3PI) lies about 30 kcal/mol above NCN(3PI(g)), but has a high barrier towards interconversion and is therefore observed experimentally. Computed harmonic frequencies for CNN are sensitive to the correlation treatment: they are reproduced well using multireference methods as well as the CCSD(T) method. High spin contamination has a detrimental effect on computed harmonic frequencies at the CCSD(T) level.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.897
Times cited: 46
DOI: 10.1016/0009-2614(94)00758-6
|
“Ab initio study of the structure, infrared spectra and heat of formation of C4”. Martin JML, François JP, Gijbels R, The journal of chemical physics 94, 3753 (1991)
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.952
Times cited: 62
|
“An ab initio study of the C3+ cation using multireference methods”. Taylor PR, Martin JML, François JP, Gijbels R, The journal of chemical physics 95, 6530 (1991)
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.952
|
“Ab initio study of the X2\Sigma+ and A 2\Pi states of the SiN radical”. Cai ZL, Martin JML, François JP, Gijbels R, Chemical physics letters 252, 398 (1996). http://doi.org/10.1016/0009-2614(96)00183-2
Abstract: The equilibrium bond length, harmonic frequency, first and second order anharmonicity constants, rotational and centrifugal distortion constants, as well as the rotation-vibrational and centrifugal coupling constants for the ground X(2) Sigma(+) and first excited A(2) Pi states of the SiN radical have been calculated at the complete active space SCF (CASSCF), multireference CI (MRCI) and coupled cluster (CCSD(T)) levels using Dunning's correlation-consistent basis sets. The excitation energy of the A(2) Pi State has also been computed at these theoretical levels. Dipole moments of SiN in the X(2) Sigma(+) and A(2) Pi states are given. Our study shows that core correlation must be considered in order to obtain satisfactory accuracy for the spectroscopic constants.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.897
Times cited: 28
DOI: 10.1016/0009-2614(96)00183-2
|
“Aberration-corrected microscopy and spectroscopy analysis of pristine, nitrogen containing detonation nanodiamond”. Turner S, Shenderova O, da Pieve F, Lu Y-G, Yücelen E, Verbeeck J, Lamoen D, Van Tendeloo G, Physica status solidi : A : applications and materials science 210, 1976 (2013). http://doi.org/10.1002/pssa.201300315
Abstract: Aberration-corrected transmission electron microscopy, electron energy-loss spectroscopy, and density functional theory (DFT) calculations are used to solve several key questions about the surface structure, the particle morphology, and the distribution and nature of nitrogen impurities in detonation nanodiamond (DND) cleaned by a recently developed ozone treatment. All microscopy and spectroscopy measurements are performed at a lowered acceleration voltage (80/120kV), allowing prolonged and detailed experiments to be carried out while minimizing the risk of knock-on damage or surface graphitization of the nanodiamond. High-resolution TEM (HRTEM) demonstrates the stability of even the smallest nanodiamonds under electron illumination at low voltage and is used to image the surface structure of pristine DND. High resolution electron energy-loss spectroscopy (EELS) measurements on the fine structure of the carbon K-edge of nanodiamond demonstrate that the typical * pre-peak in fact consists of three sub-peaks that arise from the presence of, amongst others, minimal fullerene-like reconstructions at the nanoparticle surfaces and deviations from perfect sp(3) coordination at defects in the nanodiamonds. Spatially resolved EELS experiments evidence the presence of nitrogen within the core of DND particles. The nitrogen is present throughout the whole diamond core, and can be enriched at defect regions. By comparing the fine structure of the experimental nitrogen K-edge with calculated energy-loss near-edge structure (ELNES) spectra from DFT, the embedded nitrogen is most likely related to small amounts of single substitutional and/or A-center nitrogen, combined with larger nitrogen clusters.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.775
Times cited: 37
DOI: 10.1002/pssa.201300315
|
“Accuracy and precision in model based EELS quantification”. Bertoni G, Verbeeck J, Ultramicroscopy 108, 782 (2008). http://doi.org/10.1016/j.ultramic.2008.01.004
Abstract: We present results on model based quantification of electron energy loss spectra (EELS), focusing on the factors that influence accuracy and precision in determining chemical concentrations. Several sources of systematical errors are investigated. The spectrometer entrance aperture determines the collection angle, and the effects of its position with respect to the transmitted beam are investigated, taking into account the diffraction by the crystal structure. The effect of the orientation of the sample is tested experimentally and theoretically on SrTiO3, and finally, a simulated experiment on c-BN at different thicknesses confirms the superior results of the model based method with respect to the conventional method. A test on a set of experimental reference compounds is presented, showing that remarkably good accuracy can be obtained. Recommendations are given to achieve high accuracy and precision in practice. (C) 2008 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.843
Times cited: 44
DOI: 10.1016/j.ultramic.2008.01.004
|
“Accuracy of the Hartree-Fock method for Wigner molecules at high magnetic fields”. Szafran B, Bednarek S, Adamowski J, Tavernier MB, Anisimovas E, Peeters FM, European physical journal : D : atomic, molecular and optical physics 28, 373 (2004). http://doi.org/10.1140/epjd/e2003-00320-5
Abstract: Few-electron systems confined in two-dimensional parabolic quantum dots at high magnetic fields are studied by the Hartree-Fock (HF) and exact diagoiialization methods. A generalized multicenter Gaussian basis is proposed in the HF method. A comparison of the HF and exact, results allows as to discuss the relevance of the symmetry of the charge density distribution for the accuracy of the HF method. It is shown that the energy estimates obtained with the broken-symmetry HF wave functions become exact in the infinite magnetic-field limit. In this limit the charge density of the broken-symmetry solution call be identified with the classical charge distribution.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.288
Times cited: 14
DOI: 10.1140/epjd/e2003-00320-5
|
“Accurate ab initio quartic force fields and thermochemistry of FNO and CINO”. Martin JML, François JP, Gijbels R, The journal of physical chemistry 98, 11394 (1994). http://doi.org/10.1021/j100095a022
Abstract: The quartic force fields of FNO and CINO have been computed at the CCSD(T)/cc-pVTZ level. Using an ''augmented'' basis set dramatically improves results for FNO but has no significant effect for CINO. The best computed force field for FNO yields harmonic frequencies and fundamentals in excellent agreement with experiment. Overall, the force fields proposed in the present work are probably the most reliable ones ever published for these molecules. Total atomization energies have been computed using basis sets of spdfg quality: our best estimates are Sigma D-0 = 208.5 +/- 1 and 185.4 +/- 1 kcal/mol for FN0 and CINO, respectively. The computed value for FNO suggests a problem with the established experimental heat of formation. Thermodynamic tables in JANAF style at 100-2000 K are presented for both FNO and CINO.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Times cited: 21
DOI: 10.1021/j100095a022
|
“Accurate ab initio quartic force fields for the sulfur compounds H2S, CS2, OCS and CS”. Martin JML, François JP, Gijbels R, Journal of molecular spectroscopy 169, 445 (1995). http://doi.org/10.1006/jmsp.1995.1037
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.482
Times cited: 37
DOI: 10.1006/jmsp.1995.1037
|