Partial molar properties from single molecular dynamics simulations

In this manuscript, we show how to compute partial molar properties (e.g. partial molar volumes, energies, and enthalpies) of fluid mixtures from single Molecular Dynamics simulations in the microcanonical or canonical ensemble, using only relatively simple post-processing of trajectories. The method uses least squares linear regression of local fluctuations of particle numbers and energies in combination with the Small System Method, and is in principle valid for any number of components and for any type of intermolecular interactions. For multicomponent systems, only a single simulation is needed for a given composition of the mixture. Simulations of a binary WCA mixture are used to illustrate the method, and to investigate the effect of system size.