VARIATIONAL CALCULATIONS FOR 3-ELECTRON SYSTEMS HE- AND BE+

A variational calculation involving configuration interaction has been carried out to obtain the eigenvalues of the symmetries 2S, 2Pe and 4S in He- and 2S in Be+. The eigenvalues of 1s2s2 2S, 1s2p 2 2Pe and 1s2s3s 4S have been minimized by varying the exponential parameters present in the linear combinations of Slater-type orbitals used. In He- the level 1s2s 2 2S has been minimized in matrices of order 14 and 19 (which includes 1s2s′ configurations) resulting in values of -4.3756 and -4.3614 ryd, respectively. Neither the 2Pe nor the 4S levels were found to be bound. The results for the Be + 2S multiplet, using matrices of similar order and content, are -20.2115 and -20.1736 ryd.