Fully numerical complex-coordinate Hartree-Fock calculations for the He 2s2p 1,3P degrees autodetaching states.

Abstract

A fully numerical multiconfiguration Hartree-Fock program has been modified for performance of calculations on atomic quasibound states using the complex-coordinate (complex dilation) technique. We present results of a lowest-order calculation of the 2{ital s}2{ital p} {sup 1,3}{ital P}{degree} autodetaching states of He using this method, and we examine the dilational stability of our calculations. Because the numerical method exhibits a high degree of dilational stability, we need not perform auxiliary calculations to stabilize the energy with respect to the dilation parameter, as is necessary in most basis-set calculations. We also report some small-scale multiconfiguration calculations in which we account for correlation in the closed channels but attempt no improvement of the open-channel part of the wave function. As the closed-channel space is enlarged, our results show a variational collapse of the width similar to (but more pronounced than) that observed in early basis-set studies using the dilation method. The resonance position, on the other hand, is well behaved and appears to be converging to agreement with established values.