Optimization of first-principles calculation conditions of multiplet energies in Fe3 + and Co3 + in α-Al2O3
Judo Fusamoto, Kazuyoshi Ogasawara
Department of Chemistry, Kwansei Gakuin University
Abstract
The prediction of multiplet energies of dn ions such as transition metal ions in crystals is important for the development of novel optical materials. The first-principles calculations of the multiplet energies can be performed by the discrete variational multi-electron (DVME) method which is based on the configuration-interaction (CI) approach. Although the mutiplet energies calculated by CI calculations are generally overestimated, the overestimation can be corrected by considering the configuration-dependent correction (CDC) and the correlation correction (CC). For example, the experimental multiplet energies of V3+ and Cr3+ in α-Al2O3 were well reproduced by first-principles calculations considering CDC-CC. However, for d5 and d6 ions, the conditions of CDC-CC such as the considered transition processes have not been established. In this study, in order to optimize the conditions of CDC-CC, we performed first-principles calculations of the multiplet energies of Fe3+ and Co3+ in α-Al2O3 considering CDC-CC based on various transition processes. As a result, we could optimize the conditions of CDC-CC for Fe3+ and Co3+ in α-Al2O3 and successfully reproduced the experimental multiplet energies. By consideration of CDC-CC, the repulsion between electrons was suppressed and the overestimation of the multiplet splittings was reduced.
Keywords: First-principles calculation, Multiplet, Transition metal
Topic: DV-Xa Method