On a j z-preserving propensity in molecular collisions. II. Close-coupling study of state-to-state differential cross sections

In this paper, we present and analyze accurate close-coupling results for polarization transition differential cross sections for Δj≠0 atom–diatom collisions. The systems considered are He+CO and He+HCl. Cross sections for polarization transitions defined with several choices of quantization axes are presented and discussed. We find that (a) the jz-preserving cross sections are heavily favored when a generalized apse quantization scheme is used; (b) the other quantization schemes can be factorized for transitions involving lower rotor j states in terms of the dominant jz-preserving apse quantized amplitudes; (c) this factorization implies limits on the amount of information contained in polarization measurements based on nonapse quantization axes; (d) the factorization (and, hence, its limitations) does not apply to the highest accessible rotor j states; and (e) the propensity for preserving jz when quantized along a generalized apse has important implications for the well-known CS decoupling approximation and for other possible decoupling schemes.