Investigation of isomorph-invariance in liquid methane by molecular dynamics simulation

In this paper, isomorph invariance of liquid methane is investigated by means of constant-NVT molecular dynamics simulations. According to the data extracted from simulations, equilibrium fluctuations show strong correlation between potential energy U and virial W. We also generated isomorph state points and investigated invariance of certain thermodynamic, structural, and dynamical properties. The result show methane is a strongly correlated liquid for temperatures at and above 300K such that the specific heat, radial disturbution function, and diffusion are invariant for state points generated along an isomorph curve when expressed in reduced units. Hence by knowing these properties at one state point, they can be obtained for other isomorphic state points by simple rescaling.