Transferable variable-charge interatomic potential for atomistic simulation of titanium oxides

A transferable interatomic potential for atomistic simulation of titanium o xides was obtained by parametrizing a Morse-variable-charge model with crys tal structures of rutile, anatase, brookite, TiO2-II, Ti2O3, and monoclinic high- and low-temperature Ti3O5 forms, and elastic constants of rutile. Th e transferability of the potential was assessed through lattice energy mini misation of the structures included in the fitting as well as some selected structures representing various Ti-O stoichiometries and oxidation states of Ti. In addition, the transferability of the bulk-derived potential to su rface simulation was tested by evaluating relaxation characteristics of the (100) rutile surface. The results suggest that for simulating crystal stru ctures the model is applicable across different stoichiometries. polymorphs , and Ti oxidation states. The model also is successful in predicting the b ulk moduli of various phases, the relative stability of the TiO2 polymorphs , and the relaxation of (100) rutile surface.