TY - JOUR

T1 - Use of the McQuarrie equation for the computation of shear viscosity via equilibrium molecular dynamics

AU - Chialvo, Ariel A.

AU - Debenedetti, Pablo G.

PY - 1991/1/1

Y1 - 1991/1/1

N2 - To date, the calculation of shear viscosity for soft-core fluids via equilibrium molecular dynamics has been done almost exclusively using the Green-Kubo formalism. The alternative mean-squared displacement approach has not been used, except for hard-sphere fluids, in which case the expression proposed by Helfand [Phys. Rev. 119, 1 (1960)] has invariably been selected. When written in the form given by McQuarrie [Statistical Mechanics (Harper & Row, New York, 1976), Chap. 21], however, the mean-squared displacement approach offers significant computational advantages over both its Green-Kubo and Helfand counterparts. In order to achieve comparable statistical significance, the number of experiments needed when using the Green-Kubo or Helfand formalisms is more than an order of magnitude higher than for the McQuarrie expression. For pairwise-additive systems with zero linear momentum, the McQuarrie method yields frame-independent shear viscosities. The hitherto unexplored McQuarrie implementation of the mean-squared displacement approach to shear-viscosity calculation thus appears superior to alternative methods currently in use.

AB - To date, the calculation of shear viscosity for soft-core fluids via equilibrium molecular dynamics has been done almost exclusively using the Green-Kubo formalism. The alternative mean-squared displacement approach has not been used, except for hard-sphere fluids, in which case the expression proposed by Helfand [Phys. Rev. 119, 1 (1960)] has invariably been selected. When written in the form given by McQuarrie [Statistical Mechanics (Harper & Row, New York, 1976), Chap. 21], however, the mean-squared displacement approach offers significant computational advantages over both its Green-Kubo and Helfand counterparts. In order to achieve comparable statistical significance, the number of experiments needed when using the Green-Kubo or Helfand formalisms is more than an order of magnitude higher than for the McQuarrie expression. For pairwise-additive systems with zero linear momentum, the McQuarrie method yields frame-independent shear viscosities. The hitherto unexplored McQuarrie implementation of the mean-squared displacement approach to shear-viscosity calculation thus appears superior to alternative methods currently in use.

UR - http://www.scopus.com/inward/record.url?scp=26544453259&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=26544453259&partnerID=8YFLogxK

U2 - 10.1103/PhysRevA.43.4289

DO - 10.1103/PhysRevA.43.4289

M3 - Article

AN - SCOPUS:26544453259

VL - 43

SP - 4289

EP - 4295

JO - Physical Review A

JF - Physical Review A

SN - 2469-9926

IS - 8

ER -