Effect of temperature on the symmetrization of AlOOH hydrogen bonds

Hydrogen bonding symmetrization of water-bearing minerals plays a key role in the water cycle of the deep Earth. The lower mantle is a high-temperature and high-pressure environment, and in this study a classical molecular dynamics simulation of the δ-AlOOH hydrogen bond symmetrization process is carried out using a deep learning potential model. Calculation the length of the H[sbnd]O bond reveals that AlOOH undergoes hydrogen bond symmetrization when the pressure reaches 9 GPa. The volume thermal expansion profile of AlOOH shows an anomalous phenomenon of negative correlation between phase transition pressure and temperature. The radial distribution functions gOH(r) and gHH(r) show the asymmetry of hydrogen bonding at 8 GPa and indicate the critical conditions for hydrogen bonding symmetry at 10 GPa. Calculations of the O1[sbnd]O2 bond lengths show that the critical pressure required for hydrogen bond symmetry increases with temperature. Our simulation results provide some insight into the hydrogen bonding symmetry of water-bearing minerals in the deep Earth's. © 2024 Elsevier B.V.