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.