Induced Absorption Band in the N Region of LiF Crystals by Charged Particle Irradiation at Liquid Nitrogen Temperature

抄録

Single crystals of lithium fluoride have been irradiated with deuterons or protons at liquid nitrogen temperature. In absorption spectra of the crystals immediately after irradiation, a band is observed at 542 nm in addition to the F and M bands. This band has an almost constant intensity during warming from LNT to RT. It is obscured by the other overlapping bands when the crystal is heated about 100°C or when this is aged at RT for a long time. The nature of this band is examined in connection with the so-called N₂ band, Farge’s I band and Vander Lugt’s N_c band. The following relation is believed to be most plausible: The observed absorption band is identified with the I band. The N₂ band is identified with the N_c band but may not be identified with the I band.