THERMAL DECAY OF V' CENTER IN MAGNESIUM OXIDE

The thermal decay of the X-ray induced V' center (the Seitz·V1 center) in MgO is examined as a function of temperature in the range 18° to 50°C, using the optical absorption band at 2.3 e V as a measure of the V' center concentration. It is found that the decay may be described by a bimoleeular process, involving the V' center and only one electron trapping level, in which the hole is thermally liberated from the V' center with an activation energy of 1.13±0.05eV followed by recombination with a trapped electron, or by retrapping at a cation vacancy. Thermoluminescence glow curves of the same crystal show a peak corresponding to an activation energy of 1.12±0.05 eV. The proposed reaction for the V' center decay is (Fe2+) + (V') → (Fe3+) + (V) + (photon). © 1968.