Thermodynamic model of quasiliquid formation on H2O ice: Comparison with experiment

We have developed a new thermodynamic theory of the quasiliquid layer, which has been shown to be effective in modeling the phenomenon in a number of molecular systems. Here we extend our analysis to H2O ice, which has obvious implications for environmental and atmospheric chemistry. In the model, the liquid layer exists in contact with an ice defined as a two-dimensional lattice of sites. The system free energy is defined by the bulk free energies of ice Ih and liquid water and is minimized in the grand canonical ensemble. An additional configurational entropy term arises from the occupation of the lattice sites. Furthermore, the theory predicts that the layer thickness as a function of temperature depends only on the liquid activity. Two additional models are derived, where slightly different approximations are used to define the free energy. With these two models, we illustrate the connection between the quasiliquid phenomenon and multilayer adsorption and the possibility of a two-dimensional phase tra...