Magnesium oxide single crystals have been irradiated with ultraviolet light at room temperature and the glow curves and accompanying electric current recorded simultaneously from room temperature to 300°C. The measurements of optical absorption show the disappearance of absorption bands in visible region. Trap depths of the luminescent centers are given.

• Received 28 December 1953

DOI:https://doi.org/10.1103/PhysRev.96.293