THEORETICAL-STUDY OF THE LOW-LYING STATES OF TIHE+, TINE+, TIAR+, VAR+, CRHE+, CRAR+, FEHE+, FEAR+, COHE+, AND COAR+

The potential energy curves for the manifold of molecular states dissociating to the lowest transition metal ion states derived from the 3d(n+1) and 3d(n)4s(1) occupations have been determined for selected transition-metal ion-rare gas systems. These curves have been computed using large basis sets, and the state-averaged complete-active-space self-consistent-field/multireference configuration interaction level of electron correlation treatment. In general, the families of curves derived from the 3d(n+1) and 3d(n)4s(1) metal occupations are disjoint; however, for Ti+ there is a strong mixing of the 3d(2)4s(1) and 3d(3) asymptotes, because of the small separation between the asymptotes. This mixing leads to a failure of single-reference-based techniques; this is discussed in the context of our previous single-reference-based treatments.