Molecular dynamics simulation and statistical analysis for glass transition in a Lennard-Jones system

Microstructure of glassy solids have been investigated by molecular dynamics (MD) simulation coupled with a Voronoi-Delaunay (VD) tessellation. NTP ensemble MD models are constructed from Ar atoms interacting via Lennard-Jones potential and glassy solids have been obtained by rapid quenches from an equilibrium liquid state. By utilizing the VD tessellation for a quenching process, we calculated statistical variables (expected value V-E, variance sigma(2), deviation sigma, skewness gamma(1), kurtosis gamma(2), probability density distribution function f(j) and Shannon's information entropy S) from volumes of Voronoi polyhedra V-i. The V-E-T and S-T relationships show notable inflections around 55 K showing a glass transition phenomenon. During the quench process,f(j) continuously approaches to Gaussian form while gamma(1) and gamma(2) show significant inflections below T-g indicating that microstructure and local density fluctuation of the glassy solid suddenly freeze around T-g.