Strong final-state term dependence of nondipole photoelectron angular distributions from half-filled shell atoms

It is predicted that the near-threshold nondipole photoelectron angular distribution parameters of valence ns electrons from atoms having an n d5 half-filled shell in the ground state differ markedly for different final-state terms of the residual ion. This is due to the strong term dependence of electron correlation in these systems. As an example, the nondipole 4s -photoelectron angular distribution parameters below the 3d ionization threshold of the Mn (3 d5 4 s2 S6) atom, leading to Mn+ (4 s1 S7) and Mn+ (4 s1 S5), have been calculated within the framework of the spin-polarized random phase approximation with exchange. The phenomenon should be a general property of all half-filled shell atoms and ions. © 2006 The American Physical Society