Energy band structure of calcium-oxide crystals and the electronic structure of the F center in CaO and LiF crystals by method of linear combination of atomic orbitals

A self consistent field calculation of the energy band structure of a calcium oxide crystal gives an energy gap at the gamma point of 5.93 eV in comparison with the experimental value of 7.03 eV. The initial potential for determining the electronic structure of the F center in a CaO crystal is constructed by assuming that the charge distribution of the Ca(++) and O(--) ions remains the same as in a perfect crystal, even when the F center electrons are introduced. The electronic structure of the relaxed excited states of the F center in a lithium fluoride crystal were studied by writing the Hamiltonian as the difference between the F center crystal Hamiltonian and a term corresponding to relaxation of the nearest neighbor ions.