Calculation of the Spin-Orbit Parameters for the Valence Bands of the fcc Alkali Chlorides, Alkali Bromides, and Alkali Iodides

The spin-orbit parameters for the fcc alkali chlorides, alkali bromides, and alkali iodides have been calculated. Tight-binding wave functions and potentials of a type used in earlier calculations by the author were used. Various overlap corrections were computed; of these the only significant one was found to be the correction to the normalization of the wave functions due to overlap. The theoretical spin-orbit splittings for the point $\Gamma$ in the first Brillouin zone, obtained by the assumption of $\mathrm{LS}$ coupling, were found to compare favorably with existing optical data.