Hartree-Fock calculations coupled with second-order many-body perturbation theory have been performed to study binding energies, localization, and excitation properties of an excess electron in various alkali halide clusters, ${\mathrm{Na}}_{\mathit{n}}$${\mathrm{F}}_{\mathit{n}\mathrm{-}1}$, ${\mathrm{Na}}_{\mathit{n}}$${\mathrm{Cl}}_{\mathit{n}\mathrm{-}1}$, and Lin${\mathrm{F}}_{\mathit{n}\mathrm{-}1}$ (n=2,4,5,14). The binding energies agree well with recent experimental data and three different modes of localization are corroborated. The position of the F-center absorption band in ${\mathrm{Na}}_{\mathit{n}}$${\mathrm{F}}_{\mathit{n}\mathrm{-}1}$ clusters is verified, but not for ${\mathrm{Na}}_{\mathit{n}}$${\mathrm{Cl}}_{\mathit{n}\mathrm{-}1}$. New absorption bands for ${\mathrm{Na}}_{\mathit{n}}$${\mathrm{Cl}}_{\mathit{n}\mathrm{-}1}$ and ${\mathrm{Li}}_{\mathit{n}}$${\mathrm{F}}_{\mathit{n}\mathrm{-}1}$ clusters are predicted.

• Received 5 February 1990

DOI:https://doi.org/10.1103/PhysRevB.41.7955