Photoelectron angular distributions of $\mathrm{ns}$ subshells of open-shell atoms as indicators of interchannel coupling: $\mathrm{Sc}\hspace{0.5em}4s$ photoionization

It is shown that the photoelectron-angular distribution asymmetry parameter $\beta ,$ arising from $\mathrm{ns}$ photoionization in open-shell atoms, is quite a bit more sensitive to interchannel coupling than the integrated cross section. An example of $4s$ photoionization of atomic Sc is presented. It is demonstrated that this effect can occur throughout the periodic system.