Dirac-Fock calculations of photoelectron angular distributions of the outersshells of the noble gases

Dirac-Fock calculations for the photoionization of Ne $2s$, Ar $3s$, Kr $4s$, and Xe $5s$ have been performed in pure $j-j$ coupling. The asymmetry parameter $\beta$, which characterizes the photoelectron angular distribution, is found to deviate from $\beta =2\mathrm{}$ owing to the anisotropic spin-orbit interaction. It is found that the deviation increases with increasing $Z$ owing to the increase in the spin-orbit force. The influence of exchange is also examined and its energy dependence discussed.