Theoretical Assignments of the Optical Conductivity and Energy-loss Function Spectra of EuB6

On the basis of the calculated band structure of EuB6, with a higher accuracy, the optical conductivity and energy-loss function spectra were calculated, and the results were in good agreement with the experiments. All possible interband electronic transitions, the points in the first Brillouin zone where the transitions took place, and the transition probability were figured out through specific calculations. The wave functions of the initial and final states related to individual transitions were obtained as well. The calculated results were used to analyze, in detail, the correlation between the spectral peaks and the interband electronic transitions. On the basis of this, the experimental spectra were assigned, confirming the reasonable part of the empirical assignments given by Kimura et al. and pointing out the inaccurate part, and also supplying some electronic transitions, which made an important contribution to the spectral peaks, but had not been considered by Kimura et al.