Calculation of the probability of optical transitions in strong electric fields

An algorithm is proposed for calculating the spectrum of the cross section for photoionization of carriers on deep centers in electric fields on the basis of the form function of an optical transition.An experiment and calculations were performed for the complex V_Ga-S_As in GaAs. The proposed model is compared with theoretical works based on the single-coordinate approximation. It is concluded that the single-coordinate model is applicable for describing the field-dependence of the cross section for photoionization of an electron on a V_Ga-S_As center. Data on the influence of an external electric field on the change in the moments of the form function of the absorption band of the complex V_Ga-S_As in GaAs are obtained. It is concluded that an electric field influences the adiabatic potentials of the center investigated.