Free Energy of Solute Transfer at the Ice/Water Interface

Abstract

Elucidation of processes at the ice/water interface is vital in understanding phenomena such as the mechanisms of ice nucleation, growth and melting, and the interaction of solutes at the ice/water interface. The Workman-Reynolds "freezing potential", an electrical effect generated during the freezing of dilute aqueous solutions, in which potential differences are observed across the ice-water interface during the freezing process, is an interesting example of an unsolved microscopic problem of the ice/water interface. Molecular dynamics simulations of the ice Ih/water interface are carried out using the rigid SPC/E model of water. Basal and prism plane ice Ih/water interface systems at 225K and 230K respectively, stable on the order of hundreds of thousands of picoseconds, have been prepared. Using a thermodynamic integration technique, we perform simulations of solute transfer across the interface to calculate the free energy profile of the transfer of each solute particle across the ice/water interface.