Optical properties of irradiated LiF crystals in the extreme ultraviolet.

Optical absorptions of LiF crystals irradiated with gamma rays or Van de Graaff electrons were investigated in the extreme ultraviolet region. A new absorption band at 11.1 ev wss found at the tail of the fundamental absorption band. The oscillator strength of the band is estimated to be about 0.25 on the assumption of one electron center. Behaviors of other sbsorptions observed in the process of light bleaching of F bands, are also described and discussions are given on the nature of the 222 m mu band. (auth)