Feshbach-model potential approach for the study of resonant and bound states of Be-like ions

Abstract

We present an implementaion of the Feshbach formalism to calculate energy positions and widths of doubly excited states of Be-like ions. These systems can be treated formally as two-electron problems by using a suitable model potential to describe the effect of the 1s' core. In this respect, we discuss the pertinence of using the one-parameter model potential V =2r ' -2r '(1+ar)e Energies and widths for 1s 414l' 'S' and 'P' autoionizing states of N'+ and Ne + are reported.

Resonant enhancement of the harmonic-generation spectrum of beryllium

“…obtained by Bashkin and Stoner [65]. Our results for the singly excited states given in Table II are compared with those of Bachau et al [64] and Bashkin and Stoner [65]. Our results display three-digit agreement with the experimental results of Ref.…”

“…[65], whereas they display only two-digit agreement with the theoretical results of Ref. [64]. We note that our calculations included the polarizability α c of the Be 2+ core in our potential V (r) in Eq.…”

“…One sees that there is good agreement with the theoretical results of Refs. [54,64] and the experimental results of Ref. [65].…”

“…(1), whereas those of Ref. [64] did not. The dynamic polarizability of the Be 2+ core is not expected to play a significant role, since for the laser frequencies ω L we employ, the dynamic polarizability of isoelectronic He is very close to its static one [66].…”

“…[63]), and the values of the exponential parameters β = 2.333 710 and r c = 0.4 are taken respectively from Refs. [64] and [54] in which they are determined by optimizing fits to experimental energy-level data for the Be + ion. We note that the potential V (r) in Eq.…”