1Zexpansion study of the(1s)22s

Abstract

A 1/Z expansion method *s used to calculate the eigenvalues and eigenfunctions for the (1s) 2s '8 and (1s) 2p 'I' states of the lithium isoelectronic sequence. The dipole-length and dipole-velocity forms of the oscillator strengths for the 2s-2p resonance transitions are compared mth the results of direct variational calculations for individual values of the nuclear charge Z. It is explicitly demonstrated that the length formulation of the dipole matrix element is more accurate than the velocity formulation for the 2s -2p transitions.

Optical oscillator strengths for Be II and B III

“…There appears to be no experimental information available for the higher transitions 2s -np, n>2. Several calculations have also been reported [3][4][5]. Here E e is the experimental energy, E c is the calculated energy, and w( = 1lEe) is the weight.…”

“…The computed OOS are presented in Table 2, where the results of experiment [1,2] and other calculations [3][4][5] [3] are based on an analysis of the lithium isoelectronic sequence which requires the OOS to conform to various basic spectroscopic constraints. On the other hand, Weiss [4] uses the Hartree-Fock method with configuration interaction, and Onello et al [5] uses the nuclear charge expansion method. In comparison to all these calculations, the present calculation is the simplest and the most economical.…”