Photoelectron angular distribution of 3s photoionization of atomic chlorine

The photoelectron angular distribution asymmetry parameter β for 3s electrons of atomic chlorine has been calculated using the multiconfiguration Hartree-Fock method for both bound and continuum wave functions. It is determined in the electric dipole approximation within the framework of the angular-momentum-transfer formulation. The effects of electron correlation are investigated, and it is shown that electron correlations are very important for β values corresponding to both ³P and ¹P ionic states. Our results confirm the recent experimental prediction that β for s subshell photoionization in open-shell atoms, is, in general, term and photon energy dependent and, in addition, in the case of chlorine 3s photoionization, β has minima for both terms of Cl⁺ 3s(³P,¹P), in qualitative agreement with experiment. However, our calculation of β for Cl⁺ 3s(³P,¹P) channels demonstrates that interchannel coupling should be included in order to achieve quantitative agreement with experiment.