Journal of Physical Chemistry B, Vol.107, No.10, 2333-2343, 2003
Molecular dynamics simulations of the liquid/vapor interface of aqueous ethanol solutions as a function of concentration
Molecular dynamics computer simulations are utilized to study the structural and thermodynamic properties of the liquid/vapor interface of aqueous ethanol solutions as a function of concentration. In addition, the free energy profile for inserting a single ethanol molecule into a 0.059 mole fraction aqueous ethanol solution is calculated using statistical mechanical perturbation theory. The calculated free energy for solvation of an ethanol molecule in the bulk solution, the surface tension as a function of ethanol concentration, and the average orientation of ethanol molecules at the solution/vapor interface are in agreement with the corresponding experimental data. The calculated equilibrium free-energy profile, however, exhibits a barrier to solvation that is considerably smaller than that predicted by the resistance model for mass accommodation.