[en] The electroreflection method is used to study the E₀ and E₀ + Δ₀ electron transitions in homoepitaxial n-GaP (111) films with the electron concentration of 5.7 x 10²³ m^-3 before and after irradiation with ⁶⁰Co γ-ray photons with the dose range from 10⁵ to 10⁶ rad at room temperature using the electrolythic method. Splitting of the low-energy extremum is observed after irradiation. A decrease in the internal stresses in the film as a result of irradiation with γ-ray photons is estimated from the variations in the electron-transition energy and collisional parameter of broadening. An increase in the time of energy relaxation of charge carriers after irradiation is also estimated