Multiplet structures computational method

The multiplet structures of ruby calculated by the DV-ME method with and without the correlation correction are shown in Fig. 4. The experimental values are also shown together. In this case, the multiplet structures are calculated directly using the molecular orbitals of the impurity states obtained by the cluster calculation. In the calculated results, each level is broadened by the presence of the trigonal crystal field. Although the split of each peak seems to be somewhat overestimated due to the computational errors, it can be improved by increasing the number of sampling points (2). 

To understand the mechanism of interaction between light and electrons from a view of quantum chemistry, it is necessary to calculate the electronic stmctures including many-electron interaction, which has been, however, a great problem in physics due to the difficulty on computational procedure. Most of the general methods for electronic-state calculation are carried out in the one-electron approximation, which could not be applied to the direct calculations in many-electron system, such as multiplet structure in optical spectrum. 

During the meeting, various applications of and perspectives on the DV-Xa method were discussed in detail. Among them, the usefulness of theoretical analysis using DV-Xa calculation for X-ray and electron spectroscopy such as XPS, XES (X-ray emission spectroscopy), XANES, ELNES, and AES was presented and discussed. A new universal computational method for the many-electron-state, DV-ME (DV-multielectron) method was introduced by demonstrating its advantages and possibilities for application to the calculation of the multiplet structure of the d-d transition in various transition metal oxides. Another topic was the application of the DV-Xa method to materials science. The study of... 

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