Presentation of structural properties of liquid cesium by applying cohesive energy density of the liquid state

TL;DR

This study investigates the structural properties of liquid cesium across a wide temperature range using a semiempirical Lennard-Jones potential and Gillan's algorithm, revealing distinct metal, nonmetal, and transition states.

Contribution

It introduces a new method to derive the potential function using cohesive energy density, accurately capturing liquid cesium's structural transitions and comparing well with experimental and molecular dynamics data.

Findings

Identification of three distinct structural regimes in liquid cesium.

Agreement of calculated pair correlation functions with experimental data.

Observation of a singular behavior at around 1400 K indicating a structural transition.

Abstract

The structural property of liquid cesium is investigated in the temperature range 900 K to 1900 K by application of semiempirical effective Lennard-Jones (8.5-4) pair potential function and employing Gillan s algorithm to solve Percus-Yevick equation. The potential function has been derived accurately by application of cohesive energy density in a wide range of pressure-density-temperature () data including data at the proximity of absolute zero temperature. The method is very much responsive to the liquid dynamics and leads to indication of three distinct ranges of metal, nonmetal, and metal-nonmetal transition states. The resulted pair correlation functions are well compared with the reported experimental and first-principle molecular dynamic. The calculated coordination numbers in the liquid range are in agreement with experiment particularly at low temperatures, though it is singular at about 1400 K. This observation is similar to the change from one liquid structure to another one and is verified by heights of the first peak of experimental pair correlation function as a function of temperatures. At T=973 K, the position of the first peak (r=7.27 A) is in agreement well with experimental (r=5.31 A) and with the first-principle DFT molecular dynamics (r=5.24 A).