Approximate Wave Functions for theFCenter, and Their Application to the Electron Spin Resonance Problem

The vacancy model of the $F$ center is treated by a simplified Hartree method. The ions are treated as point charges, and the potential of the lattice is computed. The simplified Hartree equation is solved variationally, and the electronic polarization is computed by a self-consistent method which takes account of the screening action of the $F$-center electron. The lattice distortion is then calculated. The resulting energies are compared with the available optical data. The agreement is good.