Quantum mechanical analysis of photofragment alignment near asymmetric resonances

Abstract

Quantum mechanical analysis is presented for the alignment of the oxygen atoms produced from the photodissociation of OH. The alignment parameters are predicted to be independent of energy across the isolated Lorentzian resonances, when only one channel contributes to indirect dissociation. When more than one channel interferes with one another, they may change very slowly. Across the asymmetric resonances, the alignments exhibit rapid variations due to the quantum interference between the indirect and the direct dissociation pathways. The alignments of O(3P2) and O(3P1) exhibit different variations, both of which are asymmetric across the asymmetric resonances. It is also shown that photoexcitation to repulsive states, coupled with bound electronic states, can give asymmetric resonances and sharp variations of the alignment, suggesting that the analysis of the dynamics of direct photodissociation by measurements of vector properties could be complicated by the effects of quantum interference.