The paper is dedicated to investigation of possible ways of stabilization of the H centres created together with F and Mg+centres in a process of decay of selftrapped exciton. As a main mode of the H centres stabilizationa capture of the H centre by magnesium-vacancy dipole and creation of V-type centre was suggested. This process was theoretically studied in the frames of model of molecular cluster which electron structure was calculated by the semi-empirical version of the Hartree-Fock method. For experimental corroboration of this process the relations between dependences of magnesium dipoles decrease on dose of gamma irradiation and corresponding dose dependences of the Mg+, Mg°, and F centres radiation creation were used.