Hyperpolarizabilities of alkali halide crystals using the local-density approximation

Static electronic hyperpolarizabilities of alkali halide crystals are computed in a local-density-approximation scheme. It is found that the anion nonlinear susceptibilities are extremely sensitive to the crystalline environment while the cation values are not. Calculations using pseudopotentials to represent overlapping neighbors are found to yield very reasonable agreement with extrapolated experimental values.