Magnetic circular dichroism of optical absorption, and optically detected electron paramagnetic resonance studies were made of X-irradiated crystals of In-doped material. The mechanism of energy storage in the crystals was found not to be simply the formation of correlated F-center and In2+-center pairs, as had previously been assumed.

U.Rogulis, J.M.Spaeth, I.Tale, E.Ruza: Radiation Effects and Defects in Solids, 1995, 134, 471-5