Assessment of particle-density transformation functions for the optimal determination of the configurational entropy of mixing in molecular liquids

We critically investigate implementation details of our recently developed approach for the calculation of the configurational entropy of mixing for multicomponent molecular liquids based on atomistic molecular dynamics simulations. In particular, we study the influence of the choice of the function that serves as a transformation from atomic coordinates to a smooth particle density on the numerical results for the entropy of mixing. We find that several common functions perform very well, yielding virtually the same numerical entropy results. A certain care is required for the choice of the central parameter of these functions, which controls the specific width of the spatial broadening for each particle. Our findings confirm the broad applicability of our computational approach for the configurational entropy of mixing for molecular liquids and provide a solid basis for choosing the correct numerical broadening parameters.