Impact of interatomic electronic decay processes on Xe 4d hole decay in the xenon fluorides

Abstract

A hole in a 4d orbital of atomic xenon relaxes through Auger decay after a lifetime of 3 fs. Adding electronegative fluorine ligands to form xenon fluoride molecules, results in withdrawal of valenceelectron density from Xe. Thus, within the one-center picture of Auger decay, a lowered Xe 4d Auger width would be expected, in contradiction, however, with experiment. Employing extensive ab initio calculations within the framework of many-body Green's functions, we determine all available decay channels in XeFn and characterize these channels by means of a two-hole population analysis. We derive a relation between two-hole population numbers and partial Auger widths. On this basis, interatomic electronic decay processes are demonstrated to be so strong in the xenon fluorides that they overcompensate the reduction in intra-atomic Auger width and lead to the experimentally observed trend. The nature of the relevant processes is discussed. These processes presumably underlie Auger decay in a variety of systems.

Ab initioGreen’s function formalism for band structures

“…89 The pole search of the one-particle Green's function is recast into a Hermitian eigenvalue problem which is a numerically stable and efficient formulation, permitting us to explore strong correlations that occur for the energetically lower lying bands of crystals. 1,10,11,12,13,14 Wannier orbitals are used in internal summations in the self-energy and allow us to exploit the fact that electron correlations are predominantly local.…”

“…The ADC form (14) reproduces the analytic structure of the Feynman-Dyson perturbation series for the dynamic self-energy as can be seen from its expansion into a geometric series:…”

“…The spectral representation (13) of the dynamic selfenergy is obtained from the ADC form (14) by solving the Hermitian eigenvalue problem…”

“…9. As is well known, it is difficult to improve band structure calculations based on density functional theory. This is in particular the case when electron correlations are strong such that in quite some cases 1,10,11,12,13,14 the oneelectron picture becomes inappropriate and corrections are needed. Nevertheless, a number of ingenious methods have been devised to improve band structure results based on density functional theory.…”

“…In molecules strong correlations for instance occur when inner valence electrons are treated. 12,13,14 With the crystal orbital ADC (CO-ADC) devised here, the spectral representation of the one-particle Green's function is obtained. We suggest a formulation of the expressions in Wannier representation instead of crystal momentum representation in order to be able to exploit the local character of the correlation hole around an electron especially in the case of crystals with a large unit cell.…”