| 1. |
- Lindgren, Ingvar, 1931, et al.
(författare)
-
Construction of accurate Kohn-Sham potentials for the lowest states of the helium atom
- 2005
-
Ingår i: International Journal of Quantum Chemistry. - : Wiley. - 1097-461X .- 0020-7608. ; 102:5, s. 1010-1017
-
Tidskriftsartikel (refereegranskat)abstract
- Accurate local Kohn-Sham potentials have been constructed for the ground 1s2 1S state and, in particular, for the lowest triplet 1s2s 3S state of the helium atom, using electron densities from many-body calculations and the procedure of van Leeuwen and Baerends. The resulting Kohn-Sham orbitals reproduce the many-body densities very accurately; furthermore, we have demonstrated that the negative of the energy eigenvalue of the outermost electron orbital agrees with the corresponding ionization energy with extreme accuracy. The procedure is also applied to the Hartree-Fock density of the 1s2s 3S state, and the Kohn-Sham eigenvalue of the 2s orbital is found to agree very well with the corresponding Hartree-Fock eigenvalue, which is the negative of the ionization energy in this model due to Koopmans' theorem. The results clearly demonstrate that there is no conflict between the locality of the Kohn-Sham potential and the exclusion principle, as claimed by Nesbet
|
|
| 2. |
- Salomonson, Sten, 1951, et al.
(författare)
-
Accurate Kohn-Sham potential for the 1s2s 3S state of the helium atom: Tests of the locality and the ionization-potential theorems
- 2005
-
Ingår i: Canadian Journal of Physics. - : Canadian Science Publishing. - 0008-4204 .- 1208-6045. ; 83:1, s. 85-90
-
Tidskriftsartikel (refereegranskat)abstract
- The local Kohn–Sham potential is constructed for the 1s2s 3S state of the helium atom, using the procedure proposed by van Leeuwen and Baerends (Phys. Rev. A, 49, 2138 (1994)) and the many-body electron density, obtained from the pair-correlation program of Salomonson and Öster (Phys. Rev. A, 40, 5559 (1989)). The Kohn–Sham orbitals reproduce the many-body density very accurately, demonstrating the validity of the Kohn–Sham model and the locality theorem in this case. The ionization-potential theorem, stating that the Kohn–Sham energy eigenvalue of the outermost electron orbital agrees with the negative of the corresponding many-body ionization energy (including electronic relaxation), is verified in this case to nine digits. A Kohn–Sham potential is also constructed to reproduce the Hartree–Fock density of the same state, and the Kohn–Sham 2s eigenvalue is then found to agree with the same accuracy with the corresponding Hartree–Fock eigenvalue. This is consistent with the fact that in this model the energy eigenvalue equals the negative of the ionization energy without relaxation due to Koopmans' theorem. Related calculations have been performed previously, particularly for atomic and molecular ground states, but none of matching accuracy. In the computations presented here there is no conflict between the locality of the Kohn–Sham potential and the exclusion principle, as claimed by Nesbet (Phys. Rev. A, 58, R12 (1998)). PACS Nos.: 31.15.Ew, 31.15.Pf, 02.30.Sa
|
|
