Condensed phase effects on the electronic momentum distribution in the warm dense matter regime

TL;DR

This paper presents ab initio calculations revealing a significant reshaping of the electron momentum distribution in warm dense beryllium due to core-valence orthogonalization effects, impacting understanding of dense plasma properties.

Contribution

It introduces a nonperturbative effect caused by core-valence wavefunction orthogonalization influencing n(p) in warm dense matter, observed via advanced x-ray scattering techniques.

Findings

Strong reshaping of Compton profile with increasing density

Orthogonalization effects influence thermodynamic properties

Observable effects with x-ray free-electron lasers

Abstract

We report ab initio calculations of the valence electron momentum distribution function n(p) and dynamic structure factor for warm dense Be at Mbar pressures. We observe an unexpected, strong reshaping of the Compton profile upon increasing density, even well before any significant core-wavefunction overlap or electride behavior occurs. We propose that this nonperturbative effect, which is due to a growing influence on n(p) of the orthogonalization of valence and core electron wave- functions with increasing density, is observable by inelastic x-ray scattering at x-ray free-electron lasers and large-scale laser-shock heating facilities, and may also be more generally important for thermodynamic properties of dense, partially-ionized plasmas.