Configurational entropy of ice from thermodynamic integration

TL;DR

This paper calculates the configurational entropy of different ice phases using thermodynamic integration and Monte Carlo simulations, providing reliable residual entropy values and comparing them with existing literature.

Contribution

It introduces a precise thermodynamic integration method with Monte Carlo simulations to determine residual entropy of ice phases, including ice Ih and ice VI.

Findings

Residual entropy of ice Ih matches literature values

Residual entropy of ice VI is higher than ice Ih

Method is validated on a 2D ice model

Abstract

The configurational entropy of ice is calculated by thermodynamic integration from high to low temperatures. We use Monte Carlo simulations with a simple energy model which reproduces the Bernal-Fowler ice rules. This procedure is found to be precise enough to give reliable values for the residual entropy s_th of different ice phases in the thermodynamic limit. First, we check it for a two-dimensional ice model. Second, we calculate s_th for ice Ih, and compare our result with those previously given in the literature. Third, we obtain s_th for ice VI, for which we find a value clearly higher than for ice Ih.