Understanding the anomalous 1/t3 time dependence of velocity correlation function in one dimensional Lennard-Jones systems

Srinivas, Goundla and Bagchi, Biman (2000) Understanding the anomalous 1/t3 time dependence of velocity correlation function in one dimensional Lennard-Jones systems. In: Journal of Chemical Physics, 112 (17). pp. 7557-7563.

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Abstract

One dimensional Lennard-Jones fluids are known to exhibit an interesting 1/t3 time (t) dependence of the velocity correlation function. The origin of this decay is apparently not well understood. We have studied this problem both by molecular dynamic simulations and by mode coupling theory. We find that this t–3 decay of the velocity autocorrelation function (VACF) arises from the coupling of the tagged particle's motion to the longitudinal current mode of the fluid. Interestingly such a decay is intern rendered possible by the Gaussian time dependence of the coherent dynamic structure factor at the relevant times. This is confirmed by the simulations of Lennard-Jones rods. The t–3 dependence is found to be dominant at low and intermediate densities. We show that the mode coupling theory provides an accurate description of the VACF both at short and long time limits.

Item Type:	Journal Article
Publication:	Journal of Chemical Physics
Publisher:	American Institute of Physics
Additional Information:	Copyright for this article belongs to American Institute of Physics (AIP).
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	29 Nov 2004
Last Modified:	19 Sep 2010 04:17
URI:	http://eprints.iisc.ac.in/id/eprint/2370

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