2019/12/20 by Rajsekhar Das, Chandan Dasgupta, Das, Rajsekhar +3 · 1 citation
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Material Dynamics and Properties #Soft Condensed Matter (cond-mat.soft) #Statistical Mechanics (cond-mat.stat-mech) #Theoretical and Computational Physics
paper · pdf · doi:10.48550/arxiv.1912.09922
openalex publication_date 2019/12/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Dynamic heterogeneity, believed to be one of the hallmarks of the dynamics of\nsupercooled liquids, is expected to affect the diffusion of the particles\ncomprising the liquid. We have carried out extensive molecular dynamics\nsimulations of two model glass-forming liquids in three dimensions to study the\ntime scales at which Fick's law of diffusion starts to set in. We have\nidentified two different Fickian timescales: one at which the mean squared\ndisplacement begins to show a linear dependence on time, and another one at\nwhich the distribution of particle displacements becomes Gaussian. These two\ntimes scales are found to be very different from each other and from the\n\α relaxation time in both systems. An interesting connection is found\nbetween one of these Fickian time scales and the time scale obtained from the\nbond-breakage correlation function. We discuss the relationships between these\ndifferent timescales and their connection to dynamic heterogeneity in the\nsystem.\n