Quantum corrections to molecular dynamics simulations of specific heat capacities of thin ices: Role of adsorption and quasi-liquid layers at interfaces

SC Wang and WP Zhao and LP Zhou and XZ Du, JOURNAL OF MOLECULAR LIQUIDS, 391, 123418 (2023).

DOI: 10.1016/j.molliq.2023.123418

The thermodynamic properties of ice under confined conditions are significantly different from those of bulk, and their mechanisms are of great significance in many fields. In this work, we analyze thin ice under three different configurations, including freestanding, attached, and nanoconfined thin ice. The molecular dynamics method is employed to calculate the specific heat capacity of ice through the energy fluctuation formula, and quantum corrections are made to the simulations. The ice thickness is varied in the range of 28.57 angstrom-121.43 angstrom to explore its effect on the specific heat capacity at constant volume. The results show that the specific heat capacities of the thin ice are significantly higher than that of the bulk ice, with a tendency to increase and then decrease to a constant, and the maximum values of the specific heat capacities of the freestanding thin ice, the attached thin ice, and the nanoconfined thin ice decrease in order. The ice-copper plate interface and the ice-vacuum interface rearrange the surrounding ice molecules, which in turn form the adsorption layer and the quasi-liquid layer, respectively. Analysis of the vibrational density of states of the thin ice shows that the interface effect and the size effect play a competing role when it is smaller than a critical thickness and they play a synergistic role when it is larger than the critical thickness. This work reveals the important effects of interfacial and size effects on the specific heat capacities of thin ice and contributes to a better understanding of the thermophysical properties of ice in different configurations in fields such as atmospheric science and biology.

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