In this work, we evaluate the interfacial free energy, γ, between ice III and liquid water along the coexistence line for the TIP4P/Ice model using the mold integration technique. The calculated γ values exceed 40 mJ/m2 across all the studied pressures. We observe a non-monotonic pressure dependence with a minimum appearing near 4000 bar, analogously to that observed for hexagonal ice at negative pressures. Furthermore, the interfacial free energy was determined for two different crystal planes at one pressure, revealing an anisotropy of less than 1%.
Sedano et al. (2026) studied this question.