Negative-energy states in the Dirac—Hartree—Fock problem: the effect of omission of two-electron integrals involving the small component
Abstract
The effect of omission of two-electron integrals involving basis functions for the small component of the wavefunction on the eigenvalue spectrum in the Dirac—Hartree—Fock problem is studied. From an analysis of the Fock matrix it is shown that omission of these integrals moves the negative-energy states down, not up. Their complete omission does not give rise to intruder states. The appearance of intruder states occurs when only some of the core integrals are omitted, due to the nature of particular contraction schemes used for the core basis functions. Use of radially localized functions rather than atomic functions alleviates the intruder state problem.
- Publication:
-
Chemical Physics Letters
- Pub Date:
- August 1992
- DOI:
- 10.1016/0009-2614(92)85950-F
- Bibcode:
- 1992CPL...196..178D
- Keywords:
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- Dirac Equation;
- Electron Emission;
- Electron Energy;
- Hartree Approximation;
- Electron States;
- Integral Calculus;
- Atomic and Molecular Physics