Time-dependent, four-point density correlation function description of dynamical heterogeneity and decoupling in supercooled liquids
- 8 January 2000
- journal article
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 112 (2) , 509-512
- https://doi.org/10.1063/1.480541
Abstract
Dynamical heterogeneity and the decoupling of diffusion and relaxation in a supercooled liquid is investigated via a time-dependent, four-point density correlation function. We show that the main contribution to the corresponding generalized susceptibility χ4(t) in a molecular dynamics simulation of a Lennard-Jones liquid arises from spatial correlations between temporarily localized (“caged”) particles. By comparing χ4(t) with a generalized susceptibility χM(t) related to a correlation function for the squared particle displacements, we demonstrate a connection between dynamical heterogeneity and the decoupling of relaxation and diffusion.Keywords
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