K-edge x-ray spectra of Mg and other simple metals: Absence of evidence for orthogonality catastrophes

Abstract

It is shown that those simple free-electron metals (e.g., Li, Na, Mg, Al), whose x-ray emission spectra do not reveal bound-exciton states, generally cannot exhibit the significantly rounded $K$-edge threshold anomalies associated with the "orthogonality catastrophe." Thus, the recently measured rounded $K$-emission spectrum of magnesium cannot be interpreted as evidence for the orthogonality-catastrophe effect.