Atomic scattering from heavy P-state atoms: role of depolarization

Abstract

The anisotropy of the potential between two atoms, one at least of which has J > ½, can cause partial re-alignment of the electronic angular momentum vector (i.e. M_J transitions) during collision. Within the framework of the semi-classical approximation, a single parameter akin to the Massey parameter is found to determine whether a given system will exhibit strong or weak coupling of the electronic to the relative atomic angular momentum. The consequence of these two coupling schemes for the position of the rainbow, the quenching of glory undulations and the magnitude of the total cross section are discussed. Particular reference is made to the metastable ³ P ₂ state of Hg and the inert gases where the fine structure splitting is much larger than the relevant part of the interatomic potential. In the case of Kr* and Xe* the rainbow and glory features are strongly dependent on the initial M_J state of the atom and the glory structure should be suppressed. In contrast, scattering from systems such as Hg*/Na or Hg*/Hg should take place under weak coupling conditions.