An isothermal–isobaric computer simulation of the supercooled-liquid/glass transition region: Is the short-range order in the amorphous solid fcc?

Abstract

[N,P,T] Monte Carlo simulations of metastable supercooled‐liquid and amorphous phases of Lennard‐Jones atoms indicate several distinct signatures for identifying the glass transition boundary; i.e., the density, enthalpy, and pair distribution function dependences on temperature and pressure are different for the two phases. The effective hard‐sphere packing fraction η_a at the glass transition boundary is verified to be the same whether the glass is prepared by temperature quenching or pressure crushing. Using η_a and liquid‐state perturbation theory, the glass transition boundary is calculated for the metastable pressure–temperature phase diagram of the Lennard‐Jones system. Finally, we argue that the evolution of the PDF structure as a function of degree of metastability suggests that the amorphous phase is a ’’distorted fcc packing.’’ A comparison with experiment is made.