We present an Arrhenius analysis of self-diffusion on the prismatic surface of ice calculated from molecular dynamics simulations using a structure-based criterion for determining the number of liquid-like molecules in the quasi-liquid layer. Calculated surface diffusion coefficients agree with available experimental data to within quoted precision. Our results indicate a positive Arrhenius curvature, implying a change in the mechanism of self-diffusion from low to high temperature, with a concomitant increase in energy of activation with the temperature. In addition, we ?nd that the surface self-diffusion is anisotropic at lower temperatures, transitioning to isotropic in the temperature range of 240�250 K. We present a framework for self-diffusion in the quasi-liquid layer on ice that aims to explain these observations. The outcomes of this work provide a baseline for the study of the surface morphology of ice crystals present in cirrus clouds and their impact on the Earth radiative budget.

Arrhenius analysis of anisotropic surface self-diffusion on the prismatic facet of ice

243rd National Meeting (2012)

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