Extended short-range order determines the overall structure of liquid gallium

Phys Chem Chem Phys. 2020 Feb 21;22(7):4122-4129. doi: 10.1039/c9cp05219d. Epub 2020 Feb 7.

Abstract

Polyvalent metal melts (gallium, tin, bismuth, etc.) have microscopic structural features, which are detected by neutron and X-ray diffraction and which are absent in simple liquids. Based on neutron and X-ray diffraction data and the results of ab initio molecular dynamics simulations for liquid gallium, we examine the structure of this liquid metal at the atomistic level. Time-resolved cluster analysis allows one to reveal that the short-range structural order in liquid gallium is determined by a range of the correlation lengths. This analysis, performed on a set of independent samples corresponding to equilibrium liquid phase, discloses that there are no stable crystalline domains and molecule-like Ga2 dimers typical for crystal phases of gallium. The structure of liquid gallium can be reproduced by the simplified model of the close-packed system of soft quasi-spheres. The results can be applied to analyze the fine structure of other polyvalent liquid metals.