This paper reports the calculation of linear optical properties and multiphoton absorption (MPA) coefficients of alkali halides $MX(M=\mathrm{N}\mathrm{a},\mathrm{}\mathrm{K};X=\mathrm{F},\mathrm{}\mathrm{C}\mathrm{l},\mathrm{B}\mathrm{r},\mathrm{}\mathrm{I})$ using the first-principles linearized augmented-plane-wave band method and the time-dependent perturbation theory. The calculations are in good agreement with available experimental data. For linear optical properties, the trend of the static dielectric constants with respect to the halides is attributed to the variation of the optical oscillator strength arising from the electronic transitions of the valence $p$ bands. For MPA coefficients the spectra of two-photon absorption given in the region of photon energy $\left(\frac{1}{2}{E}_g{,E}_g\right)$ show an increase of MPA coefficients with respect to the atomic number of the halogen elements. The polarization dependence of the MPA coefficients is also given, which promotes further experiments.

• Received 13 August 1997

DOI:https://doi.org/10.1103/PhysRevB.57.2222