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124 results on '"Lundqvist, B I"'

1. Van der Waals Density Functional for General Geometries

Author

Dion, M., Rydberg, H., Schroder, E., Langreth, D. C., and Lundqvist, B. I.

Subjects
Condensed Matter - Materials Science
Abstract

A scheme within density functional theory is proposed that provides a practical way to generalize to unrestricted geometries the method applied with some success to layered geometries [H. Rydberg, et al., Phys. Rev. Lett. 91, 126402 (2003)]. It includes van der Waals forces in a seamless fashion. By expansion to second order in a carefully chosen quantity contained in the long range part of the correlation functional, the nonlocal correlations are expressed in terms of a density-density interaction formula. It contains a relatively simple parametrized kernel, with parameters determined by the local density and its gradient. The proposed functional is applied to rare gas and benzene dimers, where it is shown to give a realistic description., Comment: 4 pages, 4 figures

Published
2004
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2. Van der Waals Density Functional for Layered Structures

Author

Rydberg, H., Dion, M., Jacobson, N., Schroder, E., Hyldgaard, P., Simak, S. I., Langreth, D. C., and Lundqvist, B. I.

Subjects
Condensed Matter - Materials Science, Condensed Matter - Soft Condensed Matter
Abstract

To understand sparse systems we must account for both strong local atom bonds and weak nonlocal van der Waals forces between atoms separated by empty space. A fully nonlocal functional form [H. Rydberg, B.I. Lundqvist, D.C. Langreth, and M. Dion, Phys. Rev. B 62, 6997 (2000)] of density-functional theory (DFT) is applied here to the layered systems graphite, boron nitride, and molybdenum sulfide to compute bond lengths, binding energies, and compressibilities. These key examples show that the DFT with the generalized-gradient approximation does not apply for calculating properties of sparse matter, while use of the fully nonlocal version appears to be one way to proceed., Comment: 5 pages, 3 figures, 1 table. Version 2: minor changes to text

Published
2003
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3. Mobility of dislocations in semiconductors

Author

Stokbro, K., Hansen, L. B., and Lundqvist, B. I.

Subjects
Condensed Matter - Materials Science
Abstract

Atomic-scale calculations for the dynamics of the 90$^0$ partial glide dislocation in silicon are made using the effective-medium tight-binding theory. Kink formation and migration energies for the reconstructed partial dislocation are compared with experimental results for the mobility of this dislocation. The results confirm the theory that the partial moves in the dissociated state via the formation of stable kinks. The correlation between glide activation energy and band gap in semiconducting systems is discussed., Comment: 4 pages, 2 figures, LaTeX, with sprocl.sty macro package. To appear in the Proceedings of ICPS Berlin July 1996

Published
1996

4. van der Waals Density Functional for Atoms and Surfaces

Author

Andersson, Y., Hult, E., Langreth, D. C., Lundqvist, B. I., Cardona, Manuel, editor, Fulde, Peter, editor, von Klitzing, Klaus, editor, Queisser, Hans-Joachim, editor, Lotsch, Helmut K. V., editor, Okiji, Ayao, editor, Kasai, Hideaki, editor, and Makoshi, Kenji, editor

Published
1996
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8. Potential-energy surfaces for excited states in extended systems.

Author

Hellman, A., Razaznejad, B., and Lundqvist, B. I.

Subjects
POTENTIAL energy surfaces, QUANTUM chemistry, DENSITY functionals, CHARGE exchange, CHEMILUMINESCENCE, HALOGENS
Abstract

With a simple and physically intuitive method, first-principles calculations of potential-energy surfaces are performed for excited states in a number of illustrative systems, including dimers (H[sub 2] and NaCl) and gas–surface systems [Cl–Na(100) and Cl[sub 2]–Na(100)]. It is based on density-functional theory and is a generalization of the Δ self-consistent field (ΔSCF) method, where electron–hole pairs are introduced in order to model excited states, corresponding to internal electron transfers in the considered system. The desired excitations are identified by analysis of calculated electron orbitals, local densities of states, and charge densities. For extended systems, where reliable first-principles methods to account for electronically excited states have so far been scarce, our method is very promising. Calculated results, such as the chemiluminescence of halogen molecules impinging on a alkali–metal surface, and the vertical (5σ→2π[sup *]) excitation within the adsorbed CO molecule on the Pd(111) surface, are in working agreement with those of other studies and experiments. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Published
2004
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23. ChemInform Abstract: A Density Functional for Sparse Matter

Author

Langreth, D. C., primary, Lundqvist, B. I., additional, Chakarova‐Kack, S. D., additional, Cooper, V. R., additional, Dion, M., additional, Hyldgaard, P., additional, Kelkkanen, A., additional, Kleis, J., additional, Kong, Lingzhu, additional, Li, Shen, additional, and et al., et al., additional

Published
2009
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24. A density functional for sparse matter

Author

Langreth, D C, primary, Lundqvist, B I, additional, Chakarova-Käck, S D, additional, Cooper, V R, additional, Dion, M, additional, Hyldgaard, P, additional, Kelkkanen, A, additional, Kleis, J, additional, Kong, Lingzhu, additional, Li, Shen, additional, Moses, P G, additional, Murray, E, additional, Puzder, A, additional, Rydberg, H, additional, Schröder, E, additional, and Thonhauser, T, additional

Published
2009
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25. Electronic, bonding, and optical properties of CeO2 and Ce2O3 from first principles

Author

Skorodumova, N. V., Ahuja, Rajeev, Simak, S. I., Abrikosov, I. A., Johansson, Börje, Lundqvist, B. I., Skorodumova, N. V., Ahuja, Rajeev, Simak, S. I., Abrikosov, I. A., Johansson, Börje, and Lundqvist, B. I.

Abstract

First-principles electronic structure calculations of cerium oxide in two forms, CeO2 and Ce2O3, are Presented. The 4f state of Ce is treated as a part of the inner core in Ce2O3 and as a valence-band-like state in CeO2,. The calculated ground-state and magnetic properties of the Ce (III) oxide are shown to be in agreement with available experimental data as well as the calculated ground-state and optical properties of Ce (IV) dioxide. The nature of the bonding in cerium oxide is discussed on the basis of an analysis of the charge-density and electron localization function distributions and described as a polarized ionic bond in both oxides., QC 20100525

Published
2001
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