Systematics of the behavior of nondipolar photoelectron angular distribution parameter gamma

Basedon relativistic Dirac-Fock-Slater calculations of the photoelectron angular distribution nondipolar parameters for the elements 1<=Z<=54 in the kinetic energy range, Ekin up to 5000 eV, the dependence of the parameter gammaon Z- and Ekin-values is discussed. This dependence has regular behavior for each subshell and can be explained using analytical expressions for nondipolar parameters. The specific behavior is expected near the Cooper minimum. This is demonstrated for the Ar 3p-subshell.