Simulation Investigation of Bulk and Surface Properties of Liquid Benzonitrile: Ring Stacking  Assessment and Deconvolution

This manuscript is devoted to classical molecular dynamics (MD) simulation studies of the bulk and surface properties of liquid benzonitrile (BZN) in the temperature range of 293-323K. The content and the simulation-analysis are inspired by our recent ab initio calculation on benzonitrile, whereas present results are to expand and develop macroscopic documentation involving data verification. We investigate the molecular stacking that involves phenyl ring, which is notably absent in the counterpart acetonitrile solvent. MD simulations of the bulk liquid unravel the hydrogen bond (C≡N⋯H) formation and strength, in the order of ortho-H >> meta-H ~>para-H. The possibility for ortho-H’s to get involved in the formation of two bonds simultaneously confirms each having - and -bonding features. The singularity centered at about 313 K found in the trend of the simulated temperature-dependent viscosity and diffusion coefficient of liquid BZN goes alongside the reported experiment, and the phenomenon may root from a change in the internal frictional motion of the molecular cluster in stacking modes. Accordingly, we used vast efforts for analysis particularly based on the deconvolution of the corresponding complex correlation functions. Specific angle-dependent correlation functions led to the recognition of the stacking molecules and their strict orientational character by utilizing relative molecular twist angles. Recognition of the strict orientational character of the stacking molecules, as a clue to the singularity in the viscosity trend, will be discussed based on specific angle-dependent correlation functions.