Hartree—Fock Theory of Atomic Properties

Abstract

A procedure is presented for the calculation of atomic properties to any desired degree of accuracy using straightforward perturbation theory (PT). The ``uncoupled'' Hartree—Fock perturbation theory (UCPT) result is shown to agree with the first term of the PT expansion, while the ``coupled'' Hartree—Fock perturbation theory (CPT) result is shown to differ from the first two terms of the PT expansion only by higher-order terms. When the CPT result is improved upon using perturbation theory, all the ``coupling'' or ``self-consistency'' terms vanish identically and the result of the PT procedure is obtained. There is thus no advantage gained in performing the more difficult computations of CPT. The ``variants'' in UCPT discussed by Langhoff et al. are shown to be leading terms in the expansion of the UCPT result itself.