Effect of higher polarization moments on collisional beats of polarizations of light upon laser excitation

A contribution is examined that is made by the anisotropic collisional relaxation of higher polarization moments--the octupole orientation and the dodecapole alignment--to the collisional generation of orientation of atomic angular momenta and to a signal of collisional beats of the circular polarization of light. On the basis of a calculation of this signal for neon atoms excited by a single-mode laser to the 2p4(3p[3/2]2), J=2 state in atmosphere of xenon, it was found that the contribution of higher polarization moments to the amplitude of the signal substantially depends on pressure and reaches 10-15% of the contribution of the main process of generation of the circular polarization--interconversion of alignment and orientation of angular momenta under the action of anisotropic collisions. This contribution distinctly manifests itself as a difference between a real signal and its approximation constructed without considering higher polarization moments