The thermal recovery processes after 80 K irradiation of NaCl:${\mathrm{Mn}}^{2+}$ have been investigated by using thermoluminescence (TL), optical absorption, and electron paramagnetic resonance (EPR). A main TL glow peak (II) is observed at about 170 K, both in pure and doped samples (the kinetics being, respectively, second and first order). It has been associated to the recombination of mobile $V_k$ centers with electron-trapped centers. For doped samples these electronic-centers have been identified as ${\mathrm{Mn}}^0$ $B$ centers; whereas for pure samples they are suggested to be $F^{-}$ centers. The kinetics of the peak as well as the change in the temperature of its maximum with manganese concentration can be accounted for, by using the theory of diffusion-limited reactions. The activation energy for the diffusion of $V_k$ centers has been found to be 0.37 eV. For doped samples, two other glow peaks at 108 K (I) and 222 K (III) are observed. Possible models for them have been advanced; in particular peak III seems to be associated to the thermal release of holes from $V_F$ centers. At variance with the data above room temperature, no correlation has been found between any of the TL peaks and an annihilation step in the $F$-center concentration.

• Received 29 October 1979

DOI:https://doi.org/10.1103/PhysRevB.23.3041