THEORETICAL-STUDY OF THE ELECTRONIC STATES OF RH-5

Geometries and energy separations of 32 low-lying electronic states of Rh-5 with different structures have been investigated. Complete activ e space multi-configuration self-consistent held method followed by la rge scale multireference singles + doubles configuration interaction c omputations that included up to 2.09 million configurations were used. Three nearly degenerate electronic states, namely, B-2(2)(C-2v) with a distorted trigonal bipyramid, (4)A(2)(C-2v) with a distorted trigona l bipyramid, and 4A,(C,,) with a distorted tetragonal geometry were fo und as candidates for the ground state of Rh-5. The calculated ionizat ion potential from the ground state structure was found to be within t he observed experimental range. The atomization and dissociation energ ies have also been computed and the results are compared with the smal ler clusters. (C) 1997 American Institute of Physics.