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181 results on '"Cottenier, S."'

59. QUADRUPOLE MOMENT OF THE 7/21 ISOMER STATE OF 43mS.

Author

CHEVRIER, R., DAUGAS, J. M., GAUDEFROY, L., ICHIKAWA, Y., UENO, H., HASS, M., HAAS, H., COTTENIER, S., AOI, N., ASAHI, K., BALABANSKI, D. L., FUKUDA, N., FURUKAWA, T., GEORGIEV, G., HAYASHI, H., IIJIMA, H., INABE, N., INOUE, T., ISHIHARA, M., and ISHII, Y.

Subjects
QUADRUPOLE moments, ELECTROMAGNETIC theory, ISOMERS, ANGULAR distribution (Nuclear physics), NUCLEAR structure
Published
2013

63. Energy-resolved Mossbauer spectroscopy with broad-band synchrotron radiation

Author

UCL - Autre, Neyens, G, Odeurs, J., Coussement, R., L'abbe, C, Cottenier, S, Ladrière, Jean, 4th International Symposium for the Industrial Applications of the Mossbauer Effect (ISIAME 96), UCL - Autre, Neyens, G, Odeurs, J., Coussement, R., L'abbe, C, Cottenier, S, Ladrière, Jean, and 4th International Symposium for the Industrial Applications of the Mossbauer Effect (ISIAME 96)

Published
1998

71. Tetravalent Doping of CeO2: The Impact of Valence Electron Character on Group IV Dopant Influence.

Author

Vanpoucke, D. E. P., Cottenier, S., Van Speybroeck, V., Van Driessche, I., Bultinck, P., and Tanaka, I.

Subjects
*FLUORITE, *CALCIUM fluoride, *DENSITY functional theory, *OXYGEN, *DOPING agents (Chemistry)
Abstract

Fluorite CeO2 doped with group IV elements is studied within the density functional theory ( DFT) and DFT + U framework. Concentration-dependent formation energies are calculated for Ce1− x Z x O2 (Z = C, Si, Ge, Sn, Pb, Ti, Zr, Hf) with 0 ≤ x ≤ 0.25 and a roughly decreasing trend with ionic radius is observed. The influence of the valence and near valence electronic configuration is discussed, indicating the importance of filled d and f shells near the Fermi level for all properties investigated. A clearly different behavior of group IVa and IVb dopants is observed: the former are more suitable for surface modifications and the latter are more suitable for bulk modifications. For the entire set of group IV dopants, there exists an inverse relation between the change, due to doping, of the bulk modulus, and the thermal expansion coefficients. Hirshfeld-I atomic charges show that charge-transfer effects due to doping are limited to the nearest-neighbor oxygen atoms. [ABSTRACT FROM AUTHOR]

Published
2014
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72. Error Estimates for Solid-State Density-Functional Theory Predictions: An Overview by Means of the Ground-State Elemental Crystals.

Author

Lejaeghere, K., Van Speybroeck, V., Van Oost, G., and Cottenier, S.

Subjects
DENSITY functional theory, SOLID state chemistry, ESTIMATES, PREDICTION models, COMPARATIVE studies, CHEMISTRY experiments
Abstract

Predictions of observable properties by density-functional theory calculations (DFT) are used increasingly often by experimental condensed-matter physicists and materials engineers as data. These predictions are used to analyze recent measurements, or to plan future experiments in a rational way. Increasingly more experimental scientists in these fields therefore face the natural question: what is the expected error for such a first-principles prediction? Information and experience about this question is implicitly available in the computational community, scattered over two decades of literature. The present review aims to summarize and quantify this implicit knowledge. This eventually leads to a practical protocol that allows any scientist—experimental or theoretical—to determine justifiable error estimates for many basic property predictions, without having to perform additional DFT calculations. A central role is played by a large and diverse test set of crystalline solids, containing all ground-state elemental crystals (except most lanthanides). For several properties of each crystal, the difference between DFT results and experimental values is assessed. We discuss trends in these deviations and review explanations suggested in the literature. A prerequisite for such an error analysis is that different implementations of the same first-principles formalism provide the same predictions. Therefore, the reproducibility of predictions across several mainstream methods and codes is discussed too. A quality factor Δ expresses the spread in predictions from two distinct DFT implementations by a single number. To compare the PAW method to the highly accurate APW+lo approach, a code assessment of VASP and GPAW (PAW) with respect to WIEN2k (APW+lo) yields Δ-values of 1.9 and 3.3 meV/atom, respectively. In both cases the PAW potentials recommended by the respective codes have been used. These differences are an order of magnitude smaller than the typical difference with experiment, and therefore predictions by APW+lo and PAW are for practical purposes identical. [ABSTRACT FROM AUTHOR]

Published
2014
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76. Swinnenet al.Reply

Author

Swinnen, B., primary, Meersschaut, J., additional, Dekoster, J., additional, Langouche, G., additional, Cottenier, S., additional, Demuynck, S., additional, and Rots, M., additional

Published
1998
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89. Electronic structure and band gap of zinc spinel oxides beyond LDA: ZnAl2O4, ZnGa2O4 and ZnIn2O4.

Author

Dixit, H., Tandon, N., Cottenier, S., Saniz, R., Lamoen, D., Partoens, B., Van Speybroeck, V., and Waroquier, M.

Subjects
ELECTRONIC structure, ZINC oxide, SPINEL group, DENSITY functionals, SEMICONDUCTORS
Abstract

We examine the electronic structure of the family of ternary zinc spinel oxides ZnX2O4 (X = Al, Ga and In). The band gap of ZnAl2O4 calculated using density functional theory (DFT) is 4.25 eV and is overestimated compared with the experimental value of 3.8-3.9 eV. The DFT band gap of ZnGa2O4 is 2.82 eV and is underestimated compared with the experimental value of 4.4-5.0 eV. Since DFT typically underestimates the band gap in the oxide system, the experimental measurements for ZnAl2O4 probably require a correction. We use two first-principles techniques capable of describing accurately the excited states of semiconductors, namely the GW approximation and the modified Becke-Johnson (MBJ) potential approximation, to calculate the band gap of ZnX2O4. The GW and MBJ band gaps are in good agreement with each other. In the case of ZnAl2O4, the predicted band gap values are >6 eV, i.e. ~2 eV larger than the only reported experimental value. We expect future experimental work to confirm our results. Our calculations of the electron effective masses and the second band gap indicate that these compounds are very good candidates to act as transparent conducting host materials. [ABSTRACT FROM AUTHOR]

Published
2011
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93. Electric-field gradients used to measure atomic short range order: <img src="/fulltext-image.asp?format=htmlnonpaginated&src=633G0XHH5BCH5FXA_html\" border="0" alt=" " /> as a case-study

Author

Cottenier, S., Meersschaut, J., Vermeire, L., Demuynck, S., Swinnen, B., and Rots, M.

Abstract

Abstract:: A scheme is presented in order to obtain complete information on atomic short range order in crystalline materials based on measuring the electric-field gradient on a probe nucleus. Limitations and possible improvements of the method are discussed. When applied to U(In0.5Sn0.5)3, short range order with In-Sn attraction is found.

Published
1999
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95. Strain analysis in ultrathin silicide layers in Fe/CsCl–57FeSi/Fe sandwiches.

Author

Croonenborghs, B., Almeida, F. M., Cottenier, S., Rots, M., Vantomme, A., and Meersschaut, J.

Subjects
SILICIDES, CESIUM, X-ray diffraction, THIN films, MOSSBAUER spectroscopy, SPECTRUM analysis
Abstract

Epitaxially stabilized iron monosilicide films with the CsCl structure (B2-FeSi) have been investigated by conversion electron Mössbauer spectroscopy and x-ray diffraction. A detailed investigation of the elastic strain in these metastable layers is presented. Using hyperfine interaction information the tetragonal distortion of the silicide lattice could be quantified for layers as thin as 14 Å. A general tendency for strain relaxation with increasing layer thickness is observed. [ABSTRACT FROM AUTHOR]

Published
2004
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97. Alternative approach to populate and study the $^{229}Th$ nuclear clock isomer

Author

Verlinde, M., Krämer, Andreas, Moens, J., Chrysalidis, K., Correia, J. G., Cottenier, S., De Witte, H., Fedorov, D. V., Fedosseev, V. N., Ferrer, R., Fraile, L. M., Geldhof, S., Granados, C. A., Laatiaoui, Mustapha, Lima, T. A. L., Lin, P.-C., Manea, V., Marsh, B. A., Moore, I., Pereira, L. M. C., Raeder, Sebastian, Van Den Bergh, P., Van Duppen, P., Vantomme, A., Verstraelen, E., Wahl, U., and Wilkins, S. G.

Subjects
7. Clean energy
Abstract

Physical review / C covering nuclear physics 100(2), 024315 (2019). doi:10.1103/PhysRevC.100.024315, Published by Inst., Woodbury, NY

98. Is the 7/2^<->_<1> isomer state of ^<43>S spherical?

Author

Chevrier, R., Daugas, J.M., Gaudefroy, L., Ichikawa, Y., Ueno, H., Hass, M., Haas, H., Cottenier, S., Aoi, N., Asahi, K., Balabanski, D.L., Fukuda, N., Furukawa, T., Georgiev, G., Hayashi, H., Iijima, H., Inabe, N., Inoue, T., Ishihara, M., Ishii, Y., Kameda, D., Kubo, T., Nanao, T., Neyens, G., Ohnishi, T., Rajabali, M.M., Suzuki, K., Takeda, H., Tsuchiya, M., Vermeulen, N., Watanabe, H., Yoshimi, A., Chevrier, R., Daugas, J.M., Gaudefroy, L., Ichikawa, Y., Ueno, H., Hass, M., Haas, H., Cottenier, S., Aoi, N., Asahi, K., Balabanski, D.L., Fukuda, N., Furukawa, T., Georgiev, G., Hayashi, H., Iijima, H., Inabe, N., Inoue, T., Ishihara, M., Ishii, Y., Kameda, D., Kubo, T., Nanao, T., Neyens, G., Ohnishi, T., Rajabali, M.M., Suzuki, K., Takeda, H., Tsuchiya, M., Vermeulen, N., Watanabe, H., and Yoshimi, A.

Abstract

We report on the spectroscopic quadrupole moment measurement of the 7/2^<−>_<1> isomeric state in ^<43>_<16>S_<27> [E^∗ =320.5(5) keV , T_<1/2>=415(3) ns], using the time dependent perturbed angular distribution technique at the RIKEN RIBF facility. Our value, ∣Q_s∣=23(3) efm^2 , is larger than that expected for a single-particle state. Shell model calculations using the modern SDPF-U interaction for this mass region reproduce remarkably well the measured ∣Q_s∣, and show that non-negligible correlations drive the isomeric state away from a purely spherical shape.

99. Is the 7/2^<->_<1> isomer state of ^<43>S spherical?

Author

Chevrier, R., Daugas, J.M., Gaudefroy, L., Ichikawa, Y., Ueno, H., Hass, M., Haas, H., Cottenier, S., Aoi, N., Asahi, K., Balabanski, D.L., Fukuda, N., Furukawa, T., Georgiev, G., Hayashi, H., Iijima, H., Inabe, N., Inoue, T., Ishihara, M., Ishii, Y., Kameda, D., Kubo, T., Nanao, T., Neyens, G., Ohnishi, T., Rajabali, M.M., Suzuki, K., Takeda, H., Tsuchiya, M., Vermeulen, N., Watanabe, H., Yoshimi, A., Chevrier, R., Daugas, J.M., Gaudefroy, L., Ichikawa, Y., Ueno, H., Hass, M., Haas, H., Cottenier, S., Aoi, N., Asahi, K., Balabanski, D.L., Fukuda, N., Furukawa, T., Georgiev, G., Hayashi, H., Iijima, H., Inabe, N., Inoue, T., Ishihara, M., Ishii, Y., Kameda, D., Kubo, T., Nanao, T., Neyens, G., Ohnishi, T., Rajabali, M.M., Suzuki, K., Takeda, H., Tsuchiya, M., Vermeulen, N., Watanabe, H., and Yoshimi, A.

Abstract

We report on the spectroscopic quadrupole moment measurement of the 7/2^<−>_<1> isomeric state in ^<43>_<16>S_<27> [E^∗ =320.5(5) keV , T_<1/2>=415(3) ns], using the time dependent perturbed angular distribution technique at the RIKEN RIBF facility. Our value, ∣Q_s∣=23(3) efm^2 , is larger than that expected for a single-particle state. Shell model calculations using the modern SDPF-U interaction for this mass region reproduce remarkably well the measured ∣Q_s∣, and show that non-negligible correlations drive the isomeric state away from a purely spherical shape.

100. A perturbed angular correlation study of Fe/Co multilayers on (110)-GaAs

Author

Swinnen, B., Dekoster, J., Meersschaut, J., Demuynck, S., Cottenier, S., and Rots, M.

Abstract

Recent results on the magnetic hyperfine fields at the 111Cd nuclear probe in MBE-grown (FexCoy)10multilayers (with x = 10, 25 and40 Å; y = 20 Å) reveal a sharp Co on Fe interface, while a diffuse interface Fe on Co is observed.

Published
1996
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