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

Srinivas, Goundla ; Bagchi, Biman (2000) Understanding the anomalous 1/t3 time dependence of velocity correlation function in one dimensional Lennard-Jones systems Journal of Chemical Physics, 112 (17). pp. 7557-7563. ISSN 0021-9606

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Official URL: http://jcp.aip.org/jcpsa6/v112/i17/p7557_s1

Related URL: http://dx.doi.org/10.1063/1.481352

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 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; 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:Article
Source:Copyright of this article belongs to American Institute of Physics.
ID Code:4237
Deposited On:13 Oct 2010 09:07
Last Modified:16 May 2016 14:55

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