SPECTROSCOPIC CONSTANTS AND POTENTIAL-ENERGY CURVES FOR OSH

Complete active space (CASSCF) followed by first-order configuration interaction (FOCI) and second-order CI (SOCI) are carried out on 21 low-lying electronic states of OsH. Spin-orbit effects are investigated using the relativistic CI (RCI) methodology. The ground state of OsH is found to be 4Π symmetry with Re = 1.606 A ̊, ωe = 2138 cm-1, De = 2.317 eV, and μe = -1.651 D in the absence of spin-orbit interactions, while the ground state is found to be a strong mixture of 4Π( 5 2) and 4Δ( 5 2) including spin-orbit coupling. Potential energy surfaces for 21 low-lying electronic states are reported. Allowed electronic transitions from the ground X4Π and some other low-lying states are predicted. The nature and bonding of the low-lying electronic states are analyzed through Mulliken populations. © 1991.