title: Evaluation of surface composition of surface active water-alcohol type mixtures: a comparison of semiempirical models.
abstract: We study adsorption at planar liquid-vapor interface of surface active binary mixtures and test three well-known models for the composition of surface phase. The models were originally presented by Guggenheim. These are compared to results for model fluids from density functional theory (DFT). The model of Laaksonen and Kulmala is in best agreement with DFT calculations. Surface mole fraction of the solute component from the Guggenheim model exceeds one for a mixture with high surface activity. The failure of the Guggenheim model is also evident in our calculations for water-methanol, water-ethanol, and water-n-propanol mixtures.
authors.affiliation: Department of Physical Sciences, University of Helsinki, P.O. Box 64, FIN-00014 Helsinki, Finland.
authors.forename: Martta
authors.initials: M
authors.lastname: Salonen
authors.forename: Jussi
authors.initials: J
authors.lastname: Malila
authors.forename: Ismo
authors.initials: I
authors.lastname: Napari
authors.forename: Ari
authors.initials: A
authors.lastname: Laaksonen
mesh_terms: D000433:1-Propanol / Q000737:chemistry; D000327:Adsorption; D000438:Alcohols / Q000737:chemistry; D000465:Algorithms; D002627:Chemistry, Physical / Q000379:methods*; D003198:Computer Simulation; D000432:Methanol / Q000737:chemistry; D015233:Models, Statistical; D008962:Models, Theoretical; D013499:Surface Properties; D013696:Temperature; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D000438:Alcohols; D014867:Water; D000433:1-Propanol; D000432:Methanol