A first principles calculation of the KLV Auger profiles of simple metals

Abstract

AbstraQ. We model the local electronicstructure around acore-ionizedsite inasimple metal self-consistently using an embedding technique. We consider the local densities of stales of Na, Mg and AI and calculate from first principles KLV Auger profiles. The success of this approach is assessed by comparison with experiment and with approximations which may be used to simplify the calculation. The agreement with experiment is on the whole good although some discrepancy arises for the case of W . , V lineshapes.

The Development of Auger Spectroscopy as a Probe of Local Electronic Structure

“…An analysis of KLV matrix elements shows that the KI,2,3 V lineshape will be dominated by Dl (E) with only a small contribution from Dl (E) while the KLI V lineshape will receive approximately equal contribu-tions from D;(E) and Dl (E) and thus show a double peak. Von Barth and Grossman's analysis [105] provided a good understanding of the KLV spectra of Na which has since been confirmed by detailed theoretical studies for the simple metals Mg and AI [110][111][112].…”

“…A detailed analysis shows that this simple assumption does not hold for Mg. It is found [119] that the ratio of the transitions rates is as strongly dependent [112].…”

“…6) makes it possible to evaluate the accuracy of the approximations usually made in analysing such profiles by means of (19) [112,119]. We have already noted the errors in assessing the energy dependence of the D; (E) and D1p(E) contributions to the KLV profiles that arise from the neglect of the energy dependence of the matrix elements ( Fig.…”

“…This has recently been obtained by self-consistent field calculations of the local electronic structure within an embedding scheme [112,119] together with an evaluation of the Auger matrix elements. The results obtained [112] at the various stages of such a calculation for pure Mg are shown in Figure 6 where the top panel, (a), gives the total LDOS and its decomposition into states of s and p character in the ground state. The introduction of a local core-hole gives rise to a screening peak in the LDOS of s character and an increase in the LDOS of p character (b).…”

“…It should be noted that the embedding scheme is less successful in calculating the KL2,3V spectral profile of these three metals [112,119] Figure 6 suggests that such spectra are little influenced by the crystal potential since the embedding scheme is essentially a calculation for a spherical electron gas which does not take account of translational symmetry. The expectation that the translational symmetry of the crystal potential has only a weak effect on the KLV profiles of simple metals is confirmed by high resolution measurements of the KLV spectra of Al obtained by Waddington [15,120] which reveal weak shoulders at the top of the peak rising from the Fermi energy similar in magnitude to the effect of the crystal potential on the valence band DOS measured in XPS [106,107].…”