Argon force field revisited: a molecular dynamic study

Abstract

We report the improvement of five argon force fields by scaling Lennard-Jones {\bf 6-12 potential (LJP)} energy ($\epsilon$) and distance ($\sigma$) parameters to reproduce liquid-vapor phase diagram and surface tension simultaneously, with molecular dynamics. Original force fields reproduce only liquid-vapor phase diagram among other properties except surface tension. Results showed that all {\bf new} force fields {\bf obtained by scaling LJP parameters reproduce well the experimental surface tension and the liquid-vapor phase diagram}, also the LJP energy and distance parameters converge in a nearby region in the $\epsilon$-$\sigma$ phase space, which is different from the original values. This study gives the intervals where the numerical values of $\epsilon$ and $\sigma$ reproduce both properties mentioned above. {\bf Furthermore, a study to calculate surface tension to avoid finite size effects is shown.}