Orthogonality catastrophe and the x-ray photoemission spectrum: Critical amplitude at finite temperatures

Abstract

Analytical treatment for the intensity of the edge singularity in the core-level x-ray photoemission spectrum given previously [Phys. Rev. B 32, 2036 (1985)] is extended to the case of finite temperatures. For a contact core-hole potential, we find the critical amplitude to be temperature independent, so that the amplitude is essentially given by $C_0$, the proportionality constant in the Anderson orthogonality theorem.