Autoionising states of He22+: adiabatic potential energy curves

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 R from 0.0 to 0.5 atomic units. The results include the potential curve of the autoionising states, 1Σsub(g) (2ssigma2, 2psigma2, 2pπ2), 1PIsub(g) (2psigma2pπ) and 1Δsub(g)(2pπ2). Both computations with and without the 1ssigmanllambda configurations are performed and the results are compared. The potential curves of states 1Σsub(g)(2ssigma2) and 1Σsub(g)(2psigma2) have a pseudo-crossing at R approximately equal to 0.2 au. (author)