When do soft spheres become hard spheres?

Autor: Khrapak, S. A., Kryuchkov, N. P., Mistryukova, L. A., Yurchenko, S. O.
Rok vydání: 2021
Předmět:
Zdroj: Physical Review E 103, 052117 (2021)
Druh dokumentu: Working Paper
DOI: 10.1103/PhysRevE.103.052117
Popis: The conventional (Zwanzig-Mountain) expressions for instantaneous elastic moduli of simple fluids predict their divergence as the limit of hard sphere (HS) interaction is approached. However, elastic moduli of a true HS fluid are finite. Here we demonstrate that this paradox reveals the soft- to hard-sphere crossover in fluid excitations and thermodynamics. With extensive \emph{in-silico} study of fluids with repulsive power-law interactions ($\propto r^{-n}$), we locate the crossover at $n\simeq 10-20$ and develop a simple and accurate model for the HS regime. The results open novel prospects to deal with the elasticity and related phenomena in various systems, from simple fluids to melts and glasses.
Comment: 6 pages, 4 figures
Databáze: arXiv