PNNL

Abstract

In this work, we briefly review recent theoretical studies of irradiation effects in oxide materials. Research based on classical mechanics and electronic structure methods to study ballistic and electronic excitation processes, respectively, in oxide materials is presented. Oxide materials have both ionic and covalent bonding interactions that make them more complex than metals and semiconductors. Hence, the modern strategy is to use electronic structure methods to help parameterize classical potential models, thus reducing the ambiguity of the potential model. Oxide materials can also support long-lived electronic excitations either as self-trapped holes and excitons or as in the formation of higher energy states, such as in a color center. We have learned that the electronic structure, in particular the low-lying conduction band states of insulators, is strongly coupled to the ionic forces, and so the excited state manifold must be mapped. In carrying out these tasks, many pitfalls are found, some discoveries are made, and many digressions are required to understand how molecular dynamics simulations can eventually couple the ballistic and electronic excitations that occur in irradiation processes in oxide materials.