Resonant Inverse Photoemission and Many-Body Effect in Nickel

Abstract

We calculate a resonant inverse photoemission spectroscopy (IPES) spectrum at the Ni 3 p core threshold (3 d n →3 p 5 3 d n +2 →3 d n +1 ), from a viewpoint of a many-body configuration interaction (CI), on the basis of the Anderson impurity model. The calculated IPES spectrum exhibits a single main peak just above the Fermi level E F under off-resonance, while it has a shoulder extending to 4 eV above E F under on-resonance conditions. Under on-resonance conditions, the main peak intensity shows a dip whose magnitude is a function of the incident electron energy e , while the shoulder is resonantly enhanced. The interference between the direct 3 d 8 →3 d 9 and resonant 3 d 8 →3 p 5 3 d 10 →3 d 9 processes and CI in both the initial and final states leads to the above result. Resonant IPES is therefore considered to be a promising method of directly determining whether a 3 d 8 configuration in the initial state, inferred by analysis of various high-energy spectroscopic data, does in fact exist. The main p...