Theoretical studies of the ground and low-lying excited electronic states of the early transition metal dihydrides with state averaged MC SCF method

The ground and low-lying excited electronic states, which are quasi-degenerated, of some dihydrides of the third-row metals, MH2 (M = Ca, Sc, Ti, V, Cr, Mn), are examined with state averaged CAS SCF calculations for the qualitative discussions of valency of metal-hydrogen bonds. The potential energy surfaces (PESs) for C2v conformations are obtained as functions of bond angles and bond lengths. The PESs of almost all of the states in dihydrides studied in the present Letter are similar to each other and the characteristics of the chemical bonds of MH are little affected by the electron configuration in the d orbitals.