CALCULATION OF PREDISSOCIATION RATES IN O-2(2-INITIO MRD-CI METHODS()BY AB)

The dissociation mechanisms of different metastable states in O-2(2+) have been investigated theoretically. Spin-orbit coupling matrix eleme nts have been determined using ab initio configuration interaction (CI ) wave functions and employing both one-and two-electron terms of the Breit-Pauli Hamiltonian. Comparisons, with data from earlier experimen tal studies [M. Lundqvist et al., J. Phys. B: At. Mel. Opt. Phys. 29 ( 1996) 499] have been made. Overall, the calculations support the inter pretation that production of ionic fragments by predissociation of met astable states is governed by spin-orbit coupling to purely repulsive electronic states. One exception is the 1 (IIg)-I-1 state, for which i t is probably necessary to take spin-spin coupling effects into consid eration, For the B-3 Sigma(u)(-) state a detailed comparison with expe riments could be made. Good agreement between theoretical and experime ntal lifetimes were obtained after a uniform shift of 0.02 Angstrom in equilibrium distance and about 0.1 eV in energy of the B-3 Sigma(u)(- ) potential curve. (C) 1998 Elsevier Science B.V.