Structural properties of liquid cesium metal by application of cohesive energy density

Abstract

The structural property of liquid cesium is investigated in the temperature range 900–1900 K by application of the 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 ( PρT) 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 the 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 = 5.27 Å ) is in agreement well with experimental ( r = 5.31 Å ) and with the first-principle DFT molecular dynamics ( r = 5.24 Å ).