Influence of elastic scattering on the measurement of core-level binding energy dispersion in x-ray photoemission spectroscopy

TL;DR

This paper investigates how elastic scattering affects the measurement of core-level binding energy dispersion in X-ray photoemission spectroscopy, highlighting potential artificial shifts that can mislead interpretations.

Contribution

It introduces a model to quantify elastic scattering effects on core-level energy measurements, emphasizing the need for careful analysis in spectroscopic studies.

Findings

Elastic scattering causes angle-dependent artificial shifts in core-level energies.

The model successfully reproduces the observed angular dependence of shifts.

Interpretations of core-level energy variations must consider elastic scattering effects.

Abstract

In the light of recent measurements of the C 1s core level dispersion in graphene [Nat. Phys. 6, 345 (2010)], we explore the interplay between the elastic scattering of photoelectrons and the surface core level shifts with regard to the determination of core level binding energies in Au(111) and Cu3Au(100). We find that an artificial shift is created in the binding energies of the Au 4f core levels, that exhibits a dependence on the emission angle, as well as on the spectral intensity of the core level emission itself. Using a simple model, we are able to reproduce the angular dependence of the shift and relate it to the anisotropy in the electron emission from the bulk layers. Our results demonstrate that interpretation of variation of the binding energy of core-levels should be conducted with great care and must take into account the possible influence of artificial shifts induced by elastic scattering.