AbstractOn the example of a KI crystal it is shown that, together with the radiative decay of electronic excitaions localized near anion vacancies (cα) and vacancy quartets (cq), their nonradiative decay also occurs at 4.2 K. VK and F centers are created at eα decay and VK centers and electron vacancy complexes are created at cq decay. These defects arise as a result of eα and eq dissociation that occurs in the electric field of an anion vacancy or of a vacancy quartet. Some details of such a process are discussed.