Energy Bands and Optical Properties of NaCl

Abstract

The energy bands of NaCl are investigated using the nonrelativistic mixed-basis (MB) method developed by one of us (ABK). Using local orbitals, the self-consistent Hartree-Fock energy bands are first obtained. Correlation effects are then taken into account and they are found to be very important in the reduction of both the energy gap, as proved in previous works, and of the valence bandwidth. Only the points $\Gamma$, $X$, $L$, and the midpoint of $\Delta$ of the first Brillouin zone were actually computed; the final energy bands have been fitted with a pseudopotential, however. The density of states for the upper valence bands and lower conduction bands, together with the imaginary part of the dielectric response function, are obtained. The results are compared with experiment and the agreement is good.