A pseudo-Hamiltonian including local and nonlocal pseudopotentials and a pseudo-spin-orbit interaction has been determined for GaSb. The 14 parameters of this pseudo-Hamiltonian are selected empirically. The lowest eight energy levels and wave functions are calculated throughout the Brillouin zone. A calculation of the imaginary part of the dielectric constant is performed in the energy range 0-6 eV, and the real parts of the dielectric constant and the reflectivity are obtained using the Kramers-Kronig relations. The calculated reflectivity is in good agreement with experiment. The pressure dependence of the band structure is discussed, and the pressure coefficients of certain energy levels are calculated, the results also being in satisfactory agreement with experiment.

• Received 6 December 1968

DOI:https://doi.org/10.1103/PhysRev.181.1163