The electronic structure and spectroscopy of V-2

The electronic structure and spectroscopy of the vanadium dimer has been st udied with semiempirical self-consistent field-configuration interaction ca lculations using the intermediate neglect of differential overlap Hamiltoni an parameterized for spectroscopy (INDO/S) including spin-orbit coupling ef fects. An approximate configuration interaction (CI) treatment is designed based on correlation effects observed in CI calculations in small active sp aces, and yields good agreement with experimental observations of state ene rgies and spin-orbit splittings. The location of a (1)Sigma(g)(+) excited s tate isoconfigurational with the ground state was determined, and calls int o question a previous assignment of an excited state observed near 1860 cm( -1). The previously observed A (3)Pi(u) <-- X (3)Sigma(g)(-) transition is assigned as a d delta(g) <-- d pi(u) promotion. In addition, an unassigned transition observed near 15 000 cm(-1) has been assigned as B (3)Sigma(u)(- ) <-- X (3)Sigma(g)(-). Both this transition and the previously observed A' (3)Sigma(u)(-) <-- X (3)Sigma(g)(-) transition are assigned as sigma(u) <- - sigma(g) promotions, in disagreement with previous assignments. A (1)Sigm a(u)(+) state isoconfigurational with the A' (3)Sigma(u)(-) state is sugges ted as a candidate for an unassigned transition in the range 11 250-12 500 cm(-1). (C) 2000 American Institute of Physics. [S0021-9606(00)30806-6].