Propensities for preserving polarization in rotationally inelastic He-O₂ collisions

Abstract

The occurrence of M-preserving propensities is investigated in He-O₂ rotationally inelastic collisions. Close-coupling calculations are used to obtain the M-dependent integral cross sections in several common quantization frames. A strong propensity for conserving e/f symmetry in JM = 0ε → J′M′ = 0ε′ transitions is observed regardless of the quantization frame.

The polarized cross sections in the kinematic and geometric apse frames (as defined by Khare et al.) are found to be almost diagonal in M. It is argued that this approximate δM = 0 selection rule in both apse frames is due to the dominance of large-angle scattering which occurs if the significant atom-molecule interaction is strongly repulsive.