A MOLECULAR DYNAMICS SIMULATION STUDY OF THE POLYHEDRAL STRUCTURE OF LIQUID ARGON DURING GLASS TRANSITION

Abstract

Polyhedron structures changes in Lennard–Jones (LJ) liquid argon containing 108 atoms are investigated by means of molecular dynamics (MD) simulations during the glass transition. The local bond orientational parameter and the bond angle distribution are calculated. In particular, a new parameter is introduced to simultaneously quantify the changes of all the major polyhedral structures: tetrahedron, hexahedron, octahedron, dodecahedron, and icosahedron. The results show that icosahedral order, hexahedral order and octahedral order increase with decreasing temperature, while tetrahedral order and dodecahedral order decrease. This indicates that the glass transition is a solidification process with complex microstructure changes.