Calculation of The Band Gap Energy and Study of Cross Luminescence in Alkaline-Earth Dihalide Crystals

The band gap energy as well as the possibility of cross luminescence processes in alkaline-earth dihalide crystals have been calculated using the ab initio Perturbed-Ion (PI) model. The gap is calculated in several ways: as a difference between one-electron energy eigenvalues and as a difference between total energies of appropriate electronic states of the crystal, both at the HF level and with inclusion of Coulomb correlation effects. In order to study the possibility of ocurrence of cross luminescence in these materials, the energy difference between the valence band and the upmost core band for some representative crystals has been calculated. Both calculated band gap energies and cross luminescence predictions compare very well with the available experimental results.Comment: LaTeX file containing 8 pages plus 1 postscript figure. Final version accepted for publication in The Journal of the Physical Society of Japan. It contains a more complete list of references, as well as a more detailed comparison with previous theoretical investigations on the subjec