Search

Your search keyword '"Van Doren, V"' showing total 348 results
Start Over Author "Van Doren, V"
348 results on '"Van Doren, V"'

1. Optimized Effective Potential Method for Polymers

Author

Sule, P., Kurth, S., and Van Doren, V.

Subjects
Condensed Matter - Materials Science
Abstract

The optimized effective potential (OEP) method allows for calculation of the local, effective single particle potential of density functional theory for explicitly orbital-dependent approximations to the exchange-correlation energy functional. In the present work the OEP method is used together with the approximation due to Krieger, Li and Iafrate (KLI). We present the first application of this method to polymers. KLI calculations have been performed for the insulating polyethylene and the results have been compared to those from other orbital-dependent potentials. Various properties of the band structure are also calculated. The single-particle band gap strongly depends on the basis set with larger basis sets yielding narrow gaps. For the highest occupied orbital energy the difference is more pronounced. In order to get the right band gap in OEP the exchange contribution to the derivative discontinuity is calculated and added to the Kohn-Sham gap., Comment: 10 pages, 1 ps figure, RevTeX

Published
1999
Full Text
View/download PDF

2. Orbital Dependent Exchange-Only Methods for Periodic Systems

Author

S"ule, P., Kurth, S., and Van Doren, V.

Subjects
Condensed Matter
Abstract

Various orbital-dependent exchange-only potentials are studied which exhibit correct long-range asymptotic behaviour. We present the first application of these potentials for polymers and by one of these potentials for molecules. Kohn-Sham type calculations have been carried out for polyethylene in order to make valuable comparison of these potentials with each other as well as with Hartree-Fock and exchange-only LDA methods. The Kohn-Sham band gap obtained with the optimized effective potetial method is corrected with the exchange contribution to the derivative discontinuity of the exchange-correlation potential. The corrected band gap obtained with the Slater's exchange potential is 9.7 eV close to the experiment., Comment: 11 pages, 2 figures. Phys. Rev. B60, 1999, in press

Published
1999

9. Density functional calculations on the structure of crystalline polyethylene under high pressures.

Author

Miao, M. S., Zhang, M.-L., Van Doren, V. E., Van Alsenoy, C., and Martins, Jose´ Lui´s

Subjects
DENSITY functionals, CRYSTALLINE polymers, QUANTUM chemistry
Abstract

The geometrical structures of the crystalline polyethylene under several different external pressures up to 10 GPa are optimized by a pseudopotential plane wave density functional method. Both local density (LDA) and generalized gradient (GGA) approximations for exchange-correlation energy and potential are used. It is found that LDA heavily underestimate the geometry parameters under ambient pressure but GGA successfully correct them and get results in good agreements with the experimental geometry. The calculated GGA volume is about 94 ų in comparison with the x-ray scattering value of about 92 ų and the neutron scattering value of 88 ų. The bulk and Young's modulus are calculated by means of several different methods. The Young's modulus along the chain ranges from about 350 to about 400 GPa which is in good agreement with the experimental results. But the bulk modulus is several times larger than those of experiments, indicating a different description of the interchain interactions by both LDA and GGA. The band structures are also calculated and their changes with the external pressure are discussed. © 2001 American Institute of Physics. [DOI: 10.1063/1.1420404]. [ABSTRACT FROM AUTHOR]

Published
2001
Full Text
View/download PDF

10. AB initio study of phonon spectra of solids

Author

Van Camp, P. E., Van Doren, V. E., Devreese, J. T., Ehlers, J., editor, Hepp, K., editor, Kippenhahn, R., editor, Weidenmüller, H. A., editor, Zittartz, J., editor, André, Jean Marie, editor, Bredas, Jean-Luc, editor, Delhalle, Joseph, editor, Ladik, Janos, editor, Leroy, Georges, editor, and Moser, Carl, editor

Published
1980
Full Text
View/download PDF

12. Schizophrenia risk from complex variation of complement component 4

Author

Sekar, A, Bialas, AR, de Rivera, H, Davis, A, Hammond, TR, Kamitaki, N, Tooley, K, Presumey, J, Baum, M, Van Doren, V, Genovese, G, Rose, SA, Handsaker, RE, Daly, MJ, Carroll, MC, Stevens, B, McCarroll, SA, Sekar, A, Bialas, AR, de Rivera, H, Davis, A, Hammond, TR, Kamitaki, N, Tooley, K, Presumey, J, Baum, M, Van Doren, V, Genovese, G, Rose, SA, Handsaker, RE, Daly, MJ, Carroll, MC, Stevens, B, and McCarroll, SA

Abstract

Schizophrenia is a heritable brain illness with unknown pathogenic mechanisms. Schizophrenia's strongest genetic association at a population level involves variation in the major histocompatibility complex (MHC) locus, but the genes and molecular mechanisms accounting for this have been challenging to identify. Here we show that this association arises in part from many structurally diverse alleles of the complement component 4 (C4) genes. We found that these alleles generated widely varying levels of C4A and C4B expression in the brain, with each common C4 allele associating with schizophrenia in proportion to its tendency to generate greater expression of C4A. Human C4 protein localized to neuronal synapses, dendrites, axons, and cell bodies. In mice, C4 mediated synapse elimination during postnatal development. These results implicate excessive complement activity in the development of schizophrenia and may help explain the reduced numbers of synapses in the brains of individuals with schizophrenia.

Published
2016

Catalog

Books, media, physical & digital resources
See catalog results