Definition and computation of intermolecular contact in liquids using additively weighted Voronoi tessellation

We present a definition of intermolecular surface contact by applying weighted Voronoi tessellations to configurations of various organic liquids and water obtained from molecular dynamics simulations. This definition of surface contact is used to link the COSMO-RS model and molecular dynamics simulations. We demonstrate that additively weighted tessellation is the superior tessellation type to define intermolecular surface contact. Furthermore, we fit a set of weights for the elements C, H, O, N, F, and S for this tessellation type to obtain optimal agreement between the models. We use these radii to successfully predict contact statistics for compounds that were excluded from the fit and mixtures. The observed agreement between contact statistics from COSMO-RS and molecular dynamics simulations confirms the capability of the presented method to describe intermolecular contact. Furthermore, we observe that increasing polarity of the surfaces of the examined molecules leads to weaker agreement in the contact statistics. This is especially pronounced for pure water.