Orientation, alignment, and hyperfine effects on dissociation of diatomic molecules to open shell atoms

Abstract

We demonstrate how magic angle detection of the circular polarization ratio can be used to probe the orientation of open shell atomic photofragments produced in photodissociation with circularly polarized light. The orientation provides new information concerning the dynamics of photodissociation which supplements that available from the alignment or from angular distribution measurements. The general theory of alignment and orientation is provided for photodissociation of diatomic molecules to open shell atoms and incorporates the asymptotic nonadiabatic interactions. Hyperfine depolarization factors are computed and tabulated for the first excited 2P3/2,1/2 states of a number of alkali atoms. They are used to transform between theoretical electronic orientation and alignment and experimentally observed values in the limit where the nuclear spins are unpolarized prior to photodissociation and where hyperfine transitions are not separated in the detection process. Orientation and alignment parameters are calculated for a variety of photodissociations in the high energy axial recoil limit.