Convergent multichannel continuum states by a general configuration interaction expansion in a B-spline basis: application to photodetachment

Abstract

We report the theoretical calculation of the total and partial cross section and asymmetry parameter for photoionization up to the N = 3 threshold. Multichannel continuum wavefunctions are obtained via a least squares solution of the Schrödinger equation employing a basis set expansion based on a primitive B-spline radial basis and a general configuration interaction (CI) form. This allows the use of a mixed full-CI and close coupling expansion in a completely general approach to improve correlation description in the continuum channels. The present algorithm correctly describes the full range of phenomena encountered with remarkable accuracy both on nonresonant cross sections and resonance structures. An accuracy of better than 0.01 Mb is estimated on both the total and partial cross sections, except for the shape resonance. In addition, Fano resonance parameters compare very well with the best methods available based on Hylleraas-type wavefunctions and complex coordinate rotation.