ELECTRONIC AND GEOMETRIC STRUCTURES OF (SCSE)-SC--SC-+( AND (SCSEH))

The (ScSe)-Sc-+ and (ScSeH)-Sc-+ molecules were investigated by determ ining the multiconfiguration self-consistent field (MCSCF) and configu ration interaction (MCSCF+1+2) wave functions for the (1) Sigma(+), (3 ) Delta and (3) Sigma(+) states of (ScSe)-Sc-+ and the (2) Delta and ( 2) Sigma(+) states of (ScSeH)-Sc-+. Ground-state (ScSe)-Sc-+ is a trip ly bonded species of (1) Sigma(+) symmetry with a bond strength of 84 kcal/mol. The (3) Delta and (3) Sigma(+) excited states lie higher in energy with bond strengths of 31 and 28 kcal/mol, respectively. The (S cSeH)-Sc-+ molecule has a (2) Delta ground state nearly degenerate wit h the excited (2) Sigma(+) State With both being differentially stabil ized by the formation of a Se-H bond. This stabilization is consistent with prior work on (ScOH)-Sc-+ and (ScSH)-Sc-+.