Calculation of the electronic structure of color centers by the multiple-scattering method

The electronic structure of the U, F, U₁, and U₂ centers in KCl has been studied using the self-consistent multiple scattering (or scattered wave) Xα method. In these calculations, clusters including the first-nearest neighbors are used to find the peak energies of various absorption bands. The calculated energies for the U and F centers agree well with the experiment. In the case of the U₂ center, two possible transitions are investigated and one agrees well with the experimental value while the other, a charge-transfer process, gives an energy too small. The hyperfine interaction of the U₂ center and the optical absorption of the U₁ center have also been studied.