Structure Factor and Electronic Structure of Compressed Liquid Rubidium

TL;DR

This study uses advanced theoretical methods to analyze the atomic and electronic structures of compressed liquid rubidium under high pressure, revealing a consistent pseudoatom structure and a uniform compression behavior reflected in structure factor scaling.

Contribution

It demonstrates that the structure factors of liquid rubidium under various high pressures scale onto a single curve when normalized, indicating uniform compression and consistent pseudoatom structure.

Findings

Structure factors align across pressures when scaled by Wigner-Seitz radius.

Pseudoatom remains unchanged under high pressure.

First peak of structure factor scales with volume as $V^{-1/3}$.

Abstract

We have applied the quantal hypernetted-chain equations in combination with the Rosenfeld bridge-functional to calculate the atomic and the electronic structure of compressed liquid-rubidium under high pressure (0.2, 2.5, 3.9, and 6.1 GPa); the calculated structure factors are in good agreement with experimental results measured by Tsuji et al. along the melting curve. We found that the Rb-pseudoatom remains under these high pressures almost unchanged with respect to the pseudoatom at room pressure; thus, the effective ion-ion interaction is practically the same for all pressure-values. We observe that all structure factors calculated for this pressure-variation coincide almost into a single curve if wavenumbers are scaled in units of the Wigner-Seitz radius $a$ although no corresponding scaling feature is observed in the effective ion-ion interaction.This scaling property of the structure factors signifies that the compression in liquid-rubidium is uniform with increasing pressure; in absolute Q-values this means that the first peak-position ($Q_1$) of the structure factor increases proportionally to $V^{-1/3}$ ($V$ being the specific volume per ion), as was experimentally observed by Tsuji et al.