AI Article Synopsis
- The study investigates the phase equilibrium between liquid water and ice Ih using the TIP4P/Ice interatomic potential through enhanced sampling molecular dynamics simulations.
- A static bias potential guided the reversible transition between phases by employing a specific order parameter tailored for crystallizing the hexagonal diamond structure of oxygen in ice Ih.
- The simulations reveal a melting temperature of 270 K, consistent with other methods, and highlight the presence of proton disorder in the ice Ih configurations.
Article Abstract
We study the phase equilibrium between liquid water and ice Ih modeled by the TIP4P/Ice interatomic potential using enhanced sampling molecular dynamics simulations. Our approach is based on the calculation of ice Ih-liquid free energy differences from simulations that visit reversibly both phases. The reversible interconversion is achieved by introducing a static bias potential as a function of an order parameter. The order parameter was tailored to crystallize the hexagonal diamond structure of oxygen in ice Ih. We analyze the effect of the system size on the ice Ih-liquid free energy differences, and we obtain a melting temperature of 270 K in the thermodynamic limit. This result is in agreement with estimates from thermodynamic integration (272 K) and coexistence simulations (270 K). Since the order parameter does not include information about the coordinates of the protons, the spontaneously formed solid configurations contain proton disorder as expected for ice Ih.
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