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Correlation effects to the expectation values of atomic systems

✍ Scribed by Richard E. Brown; S. Larsson

Publisher
John Wiley and Sons
Year
1977
Tongue
English
Weight
517 KB
Volume
12
Category
Article
ISSN
0020-7608

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✦ Synopsis

Abstract

The Hartree‐Fock and first natural spin determinants were compared as reference determinants for calculating various one‐electron properties such as ρ(0), γ€ˆΒ½βˆ‡γ€‰, γ€ˆr^βˆ’2^〉,…, γ€ˆr^3^〉, and r^βˆ’1^~12~〉. Calculations were made on various small atoms and their positive and negative ions. For nearly all the expectation values studied, the first natural spin orbital determinant gave consistently superior results. In particular, the Hartree‐Fock functions gave markedly inferior results for some long range properties such as the magnentic susceptibilities of negative ions. The major correlation error in the expectation values is primarily an orbital effect which may be accounted for by including correlation terms in the one‐particle Hamiltonian. Such approximate Brueckner or best overlap orbitals should reproduce most one‐electron expectation values accurately.

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