Back to Search Start Over

Fluid transport properties by equilibrium molecular dynamics. I. Methodology at extreme fluid states

Authors :
Alain H. Fuchs
Bernard Rousseau
Dag Kristian Dysthe
Source :
The Journal of Chemical Physics. 110:4047-4059
Publication Year :
1999
Publisher :
AIP Publishing, 1999.

Abstract

The Green-Kubo formalism for evaluating transport coefficients by molecular dynamics has been applied to flexible, multicenter models of linear and branched alkanes in the gas phase and in the liquid phase from ambient conditions to close to the triple point. The effects of integration time step, potential cutoff and system size have been studied and shown to be small compared to the computational precision except for diffusion in gaseous n-butane. The RATTLE algorithm is shown to give accurate transport coefficients for time steps up to a limit of 8 fs. The different relaxation mechanisms in the fluids have been studied and it is shown that the longest relaxation time of the system governs the statistical precision of the results. By measuring the longest relaxation time of a system one can obtain a reliable error estimate from a single trajectory. The accuracy of the Green-Kubo method is shown to be as good as the precision for all states and models used in this study even when the system relaxation time becomes very long. The efficiency of the method is shown to be comparable to nonequilibrium methods. The transport coefficients for two recently proposed potential models are presented, showing deviations from experiment of 0%–66%.

Details

ISSN :
10897690 and 00219606
Volume :
110
Database :
OpenAIRE
Journal :
The Journal of Chemical Physics
Accession number :
edsair.doi...........ed142c72d420861e96171ba324dfac4e