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

TY - JOUR

T1 - Effect of cut-off distance used in molecular dynamics simulations on fluid properties

AU - Huang, Cunkui

AU - Li, Chunli

AU - Choi, Phillip Y.K.

AU - Nandakumar, K.

AU - Kostiuk, Larry W.

N1 - Funding Information: The financial support from the NSERC for the authors (P.C., K.N. and L.W.K) is gratefully acknowledged. C.H. thanks the financial support from the PhD scholarship at the University of Alberta and the NSERC Postgraduate Scholarship.

PY - 2010/9

Y1 - 2010/9

N2 - 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.

AB - 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.

KW - canonical ensemble

KW - isothermal-isobaric ensemble

KW - molecular dynamics

KW - role attractive force

UR - http://www.scopus.com/inward/record.url?scp=77958192232&partnerID=8YFLogxK

U2 - 10.1080/08927022.2010.489556

DO - 10.1080/08927022.2010.489556

M3 - 文章

AN - SCOPUS:77958192232

SN - 0892-7022

VL - 36

SP - 856

EP - 864

JO - Molecular Simulation

JF - Molecular Simulation

IS - 11

ER -