A theoretical model for predicting homogeneous ice nucleation rate based on molecular kinetic energy distribution

Abstract

An accurate description of homogeneous ice nucleation (HIN) rate strongly relies on the availability of data of ice-water interface energy and activation energy when water molecules cross the ice-water interface. However, it proves extremely challenging to experimentally measure the values of these two quantities for the supercooled water. In this study, a theoretical model based on the molecular kinetic energy distribution is presented, thus avoiding the need to specifying the above two parameters. The predicted HIN temperatures under different pressures agree with the experimental data with deviations less than 3%. Nonlinear variations of ice germ size and concentration were found, which suggests it might be erroneous to utilise the data obtained under high temperatures to linearly extrapolate water characteristics in low-temperature regions. Significant improvements in model prediction accuracy were achieved after the inclusions of temperature fluctuation and droplet internal high pressure. The presentmodel proves capable of accurately predicting the HIN rate over temperatures down to 190 K.