Electron Tunneling and Schottky Ionization from ExcitedFCenters in an Electric Field

It is known that an applied electric field can ionize an excited $F$ center. Assuming a simple Coulomb field the probability of this process is calculated for tunneling and for Schottky ionization. The results compare satisfactorily with experiment and they lead to the possibility of an evaluation of the separation between the excited state of an $F$ center and the conduction band adjusted to the excited state.