极端条件下铁的相互作用势OA

The physical properties of iron under extreme high-pressure and high-temperature conditions are crucial for understanding the internal structure and evolutionary processes of Earth and terrestrial planets.To characterize the dynamic behavior of iron under the extreme conditions inside super-Earths,we combine first-principles molecular dynamics simulations with experimentally measured high-pressure melting curves to construct an embedded-atom potential applicable across ultra-high pressures and temperatures.This potential is fitted to multiple properties of the body-centered cubic(BCC),hexagonal close-packed(HCP),and liquid phases over 400 GPa to 1 TPa and 6 000 to 10 000 K,including the elastic constants of the solid phases,the radial distribution functions of the liquid,and experimentally determined melting data.We systematically validate the potential across different pressure-temperature conditions and found that it accurately reproduces the pressure and temperature dependence of solid elastic constants,and matches liquid radial distribution functions at three representative pressure-temperature conditions.Moreover,it predicts melting curves that lie within experimental uncertainties and agree well with previous first-principles simulations.Thermodynamic calculations based on this potential further show that the HCP phase remains thermodynamically stable between 400 GPa and 1 TPa,while the BCC phase is metastable.This potential provides a reliable atomistic tool for large-scale simulations of nucleation,crystallization,and solid-liquid coexistence in the cores of super-Earths.Moreover,the potential and associated dataset lay the groundwork for future extensions to multicomponent Fe alloys and their properties under ultra-high-pressure conditions.