Time-dependent, four-point density correlation function description of dynamical heterogeneity and decoupling in supercooled liquids

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...

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Bibliographic Details
Published in:The Journal of chemical physics 2000-01, Vol.112 (2), p.509-512
Main Authors: Glotzer, Sharon C., Novikov, Vladimir N., Schrøder, Thomas B.
Format: Article
Language:English
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Summary: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.
ISSN:0021-9606
1089-7690
DOI:10.1063/1.480541