HIGH-SPIN ELECTRONIC STATES OF THE RHODIUM TRIMER (RH3)

Ab initio studies employing complete active space multi-configuration self-consistent field followed by large-scale multi-reference configuration interaction calculations which included more than 3 million configurations on high-spin sextet, octet, decet and low-spin doublet states of rhodium trimer (Rh3) are carried out. Our computations yield three nearly degenerate sextet states as candidates for the ground state confirming the recent ESR spectra of Rh3 which have revealed that the ground state of Rh3 has S = 5/2. The geometries of all high-spin sextet and octet states are very acute isosceles triangles. The Mulliken population analyses confirm the ESR spectral inference that the unpaired electrons reside on the 4d orbitals of Rh atoms.