AN IMPROVED REPRESENTATION FOR THE HIGH-DENSITY STRUCTURE OF LENNARD-JONES SYSTEMS - FROM LIQUID TOWARD GLASS

Citation
D. Gazzillo et Rg. Dellavalle, AN IMPROVED REPRESENTATION FOR THE HIGH-DENSITY STRUCTURE OF LENNARD-JONES SYSTEMS - FROM LIQUID TOWARD GLASS, The Journal of chemical physics, 99(9), 1993, pp. 6915-6922
Citations number
44
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics, Atomic, Molecular & Chemical
Journal title
ISSN journal
0021-9606
Volume
99
Issue
9
Year of publication
1993
Pages
6915 - 6922
Database
ISI
SICI code
0021-9606(1993)99:9<6915:AIRFTH>2.0.ZU;2-P
Abstract
We show that a modified hypernetted-chain (MHNC) integral equation wit h a properly chosen hard sphere bridge function can yield an excellent representation for the high-density structure and thermodynamics of m onatomic Lennard-Jones (LJ) systems, continuously from fluid to superc ooled liquid and glassy states. In particular, the theory is able to r eproduce the gradual development of the second peak splitting in the r adial distribution function. The LJ bridge function is approximated wi th a hard sphere bridge function calculated through a slight modificat ion of a formula due to Malijevsky and Labik (ML). To select the equiv alent hard sphere diameter d, several methods are tested. First, a cri terion proposed by Rosenfeld and Blum and, second, a best fit of struc tural and thermodynamic simulation data; finally, an empirical paramet rization for d as a function of density and temperature. For stable fl uid states the predictions of the MHNC-ML theory are successfully comp ared with a wide set of simulation results from the literature. For su percooled liquid and glassy states the comparison is made with a molec ular dynamics simulation of an isochoric quench, which we have perform ed.