The monotonicity behavior of density profiles at vapor-liquid interfaces of mixtures

In their seminal monograph ’Molecular Theory of Capillarity’, Rowlinson and Widom describe different possible shapes density profiles at the vapor-liquid interface mixtures. They postulated that in some instances, could possibly be non-monotonic, exhibiting either a maximum and/ or minimum. This contribution revisits this statement light four decades posterior research. We summarize distinct morphologies suggested literature recognizing condition single minimum profile has not yet been reported. Interfacial with as well fully monotonic have observed reported extensively. The case simultaneous is more controversial, it only predicted using theoretical approaches such gradient theory (DGT). ambiguity further investigated work example cyclohexane + butanol. Both DGT combination several equations state molecular dynamics simulations are used. results from two methods found to contradictory: while predict maximum/minimum structure, computer experiment indicate profiles. thereby emphasizes for highly non-ideal mixtures should taken granted.