Eur. Phys. J. B 54, 291-297 (2006)
https://doi.org/10.1140/epjb/e2007-00005-y

Interatomic potential effects on dynamical heterogeneities in liquid SiO₂

Dept. of Physics, Institute of Technology, HoChiMinh City National University, 268 Ly Thuong Kiet Str., Distr. 10, HochiMinh City, Vietnam

Corresponding author: ^a vvhoang2002@yahoo.com

Received: 16 February 2006
Revised: 29 November 2006
Published online: 13 January 2007

Abstract

Dynamical heterogeneities (DH) in low density liquid SiO₂ have been investigated by molecular dynamics (MD) method. Simulations were done in the basic cube under periodic boundary conditions containing 3000 particles with the pair interatomic potentials, which have a weak electrostatic interaction and a Morse type short range interaction (PMSI). We have evaluated the non-Gaussian parameter for the self part of the van Hove correlation function and we found a clear evidence of the existence of DH in low density liquid SiO₂. Moreover, the atomic displacement distribution (ADD) in a model has been obtained and it deviates from a Gaussian form. The results have been compared with those obtained in another liquid SiO₂ system with the Born-Mayer interatomic potentials (BMP) in order to observe the interatomic potential effects on the DH in the system and indeed, the effects are strong. Calculations showed that particles of extremely low or fast mobility have a tendency to form a cluster and mean cluster size of most mobile and immobile particles in PMSI models increases with decreasing temperature. In contrast, no systematic changes have been obtained for the most mobile and immobile particles in BMP models. Calculations show that there is no relation between local particle environment and particle mobility in the system.