Understanding Relaxation\nin the Kob-Andersen Liquid\nBased on Entropy, String, Shoving, Localization, and Parabolic Models

We assess the validity of a range of models of glass\nformation\nbased on molecular dynamics simulation results of the Kob-Andersen\n(KA) model system under a wide range of constant volume and constant\npressure conditions. These models include the Adam–Gibbs model\nemphasizing configurational entropy, the string model emphasizing\ncollective particle exchange motion, the shoving model emphasizing\nmaterial elasticity, the localization model emphasizing dynamical\nfree volume, and parabolic models based on the ideas of dynamic facilitation\nand, alternatively, the hypothesis that glass formation involves an\navoided critical point. We demonstrate that these seemingly disparate\nmodels all provide a reasonable description of structural relaxation\nand diffusion data for the KA model system under all simulation conditions\nconsidered. Hence, the present study points to some unity in our understanding\nof the relationship between leading models of glass formation, supporting\ninferences drawn from previous studies of polymeric glass-forming\nliquids.