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

Abstract

ABSTRACTIn 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.