A molecular dynamics study concerning the effect of high-temperature and high-pressure on the structure and phase transition of Fe₂O₃ material

This paper uses Molecular Dynamics (MD) method to study the influence of high temperature (T) and high pressure (P) on the structure and phase transition of Fe₂O₃ materials. The results show that, when increasing the temperature from T = 300 K to T = 7000 K, P = 0.0 GPa, the size (1) of the Fe₂O₃ materials increases, the energy (E) increases, the length link (r) decreased, the number of structural units FeO₄, FeO₅ increased, and FeO₆ decreased. Similarly, as the pressure (P) is increased, from P = 0 GPa to P = 360 GPa at temperatures T, l decreases, E increases, r decreases, FeO₄ decreases and disappears, FeO₅ decreases, and FeO₆ increases at high P with P ≥ 150 GPa, FeO₅ disappeared at P ≥ 250 GPa and only FeO₆ appeared at T = 2300, 7000 K. In addition, when increasing T, P, the bond angle of Fe–O–Fe, O–Fe–O decreases, E increases, r decreases, l increases when T increases and l decreases when P increases, leading to the number of structural units FeO₄, FeO₅ increasing and FeO₆ decreasing when T increases and vice versa when P increases. In addition, the phase transition temperature (T_m), T_m = 2300 K was determined. All the obtained results will be the basis for future experimental studies of amorphous Fe₂O₃ materials.