Angular-momentum transfer due to postcollision interaction in atomic inner ns2 -shell photoionization

A concrete mechanism of angular-momentum transfer in photoionization process is proposed for electron photoemission from deep inner atomic shells. It is demonstrated that the leading contribution to angular-momentum transfer is provided by postcollision interaction of the photoelectrons and Auger electrons. The standard theoretical approach to postcollision interaction has been considerably improved by taking into account angular-momentum transfer. The theory developed is applied to the photoionization of $1{s}^{2}$ shell in Ar. Calculations show the noticeable influence of angular-momentum transfer on the photoelectron angular distribution.