Autoionising states of He22+: adiabatic potential energy curves

Abstract

The adiabatic potential energy curves of the He₂²⁺ system are obtained by the configuration-interaction method using 33 terms of one-centre Slater-type orbitals as basis functions. The calculation is carried out in the range of internuclear distance. The calculation is carried out in the range of internuclear distance R from 0.0 to 0.5 atomic units. The results include the potential curves of the autoionising states, ¹ Sigma _g(2s sigma ²,2p sigma ²,2p pi ²), ¹ Pi _g(2p sigma 2p pi ) and ¹ Delta _g(2p pi ²). Both computations with and without the 1s sigma nl lambda configurations are performed and the results are compared. The potential curves of states ¹ Sigma _g(2s sigma ²) and ¹ Sigma _g(2p sigma ²) have a pseudo-crossing at R approximately=0.2 au.