Effect of cut-off distance used in molecular dynamics simulations on fluid properties

Cunkui Huang, Chunli Li, Phillip Y.K. Choi, K. Nandakumar, Larry W. Kostiuk

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

The effect of cut-off distance used in molecular dynamics (MD) simulations on fluid properties was studied systematically in both canonical (NVT) and isothermal-isobaric (NPT) ensembles. Results show that the cut-off distance in the NVT ensemble plays little role in determining the equilibrium structure of fluid if the ensemble has a high density. However, pressures calculated in the same NVT ensembles strongly depend on the cut-off distance used. In the NPT ensemble, cut-off distance plays a key role in determining fluid equilibrium structure, density and self-diffusion coefficient. The characteristic of the radial distribution function of fluid in NPT ensembles depending on the cut-off distance used in MD simulations means that the WCA theory (a perturbation theory developed by Weeks, Chandler and Andersen) is not suitable for NPT ensembles because the assumption (the effect of the attractive force in determining the liquid structure is negligible) used in the WCA theory is not valid. The dependence of fluid properties on the cut-off distance also indicates that using the WCA potential (the repulsive part of the intermolecular potential proposed in the WCA theory) to calculate fluid transport in heterogeneous systems could lead to significant errors or incorrect results.

Original languageEnglish
Pages (from-to)856-864
Number of pages9
JournalMolecular Simulation
Volume36
Issue number11
DOIs
StatePublished - Sep 2010
Externally publishedYes

Keywords

  • canonical ensemble
  • isothermal-isobaric ensemble
  • molecular dynamics
  • role attractive force

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