Continuous version of a square-well potential of variable range and its application in molecular dynamics simulations

ABSTRACT

In this work, we present a simple mathematical expression for a continuous version of the square-well (SW) discontinuous potential of variable range (). This expression can be useful in theoretical statistical mechanics methods and specially in conventional molecular dynamics (MD) simulations. To illustrate the latter point, the continuous version of some SW potentials of variable range were selected and studied with continuous MD. SW single state thermodynamic and structural properties (vapour, liquid and solid), vapour–liquid phase diagrams and surface tensions accurately reproduce available simulation data obtained by Monte Carlo and discontinuous MD simulation methods. This expression can be easily implemented in popular simulation packages (GROMACS, NAMD, CHARMM, DLPOLY, EXPResSo, HOOMD, TINKER, ls1 mardyn, etc.) that can be useful to study more complex systems. Besides we also present a continuous version for the square-shoulder potential.

GRAPHICAL ABSTRACT

Keywords:

• Molecular dynamics simulation
• continuous square-well potential
• continuous square-shoulder potential

Acknowledgements

It is a pleasure to contribute to this special issue dedicated to Daan Frenkel as we have learned so much along these years from his books, papers and important contribution to the area of the computer simulation of fluids.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

I. M. Zerón is grateful for the Ph.D. scholarship provided by CONACYT (México). C. Vega would like to thank Project FIS2016-78117-P (Ministerio de Economía y Competividad) for funding. A. L. Benavides thanks the University of Guanajuato under grants 227/2018 of the Convocatoria Institucional de Investigación Científica (CIIC) 2018 and 876/2016-2017. National Laboratory UG-UAA-Conacyt (Consejo Nacional de Ciencia y Tecnología) (123732) is also acknowledged for computing resources.