Simple wave functions for(1s)(ns)1,3Sand(1s)(np)1,3Pstates of He and isoelectronic ions

Abstract

Model wave functions are developed for the excited $(1s)(\mathrm{ns}){}^{1,3}S$ and $(1s)(\mathrm{np}){}^{1,3}P$ states of He and isoelectronic ions, incorporating the asymptotic behavior when one of the electrons is far away, coalescence property when it is close to the nucleus, and cusp property when the two electrons are close to each other. They lead to accurate values for the energies and other properties, and provide an insight into their physical structure.