Pseudopotential Calculation of the Optical Constants of NaCl and KCl

The electronic band structure and optical constants of NaCl and KCl are calculated using the empirical pseudopotential method (EPM). The NaCl band structure was calculated using the standard EPM; however, for KCl we have added a nonlocal $d$-wave potential similar to that used by Falicov and Lee for potassium. The prominent structure in the measured optical spectrum of these crystals is identified.