On the separation of initial and final state effects in photoelectron spectroscopy using an extension of the auger-parameter concept

Abstract

First, we show that the quantity Δβ( i) = Δ E A( kii) + 2Δ E B ( i) — Δ E B ( k) is directly related to the final state relaxation contribution Δ E R ( i) of the binding energy shift Δ E B ( i). Δ E A ( kii) is the kinetic energy shift of the Auger transition which corresponds to the decay of a hole state with a hole in level k into a final state with two holes in level i. The shift parameter Δβ( i), which is based on information on two binding energies, is conceptually similar to Wagner's Auger parameter. To establish the relation between Δβ( i) and Δ R( i) one needs, however, less drastic approximations than in the case of Auger parameter shifts. The only approximation necessary is the assumption that Δ R( i) is determined by coulomb contributions. Secondly, we use Δβ ( i) to analyse the experimental data of eighteen gaseous phosphorus-containing compounds obtained by Sodhi and Cavell 1 1 See ref. 1. . It is shown that Δ R(P 2 p ) is strongly related to changes in the polarizability of the ligands. The initial state effects derived from our study deviate from those expected on the basis of simple electronegativity considerations.