Abstract
Color centers, produced by 50-kV x rays, have been studied in the rutile-structured Mg, largely at room temperature. An initial, slightly anisotropic, absorption band near 260 nm is tentatively identified as due to centers. Subsequent optical bleaching results in the formation of a strong band at 370 nm and several weak bands, including one at 320 nm. Both of these appear only for and are believed to be due to centers. This choice of models is suggested, in part, by the observation of typical trapped-electron ESR spectra in irradiated samples. Bleaching studies show that the 320-nm band arises from centers lying along the directions, while the 370-nm band seems to be cylindrically symmetric about the axis. Furthermore, the 320-nm band is reversibly convertible into the 370-nm band. Selection rules have been derived for transitions in each of the four possible -center configurations permitted in the rutile structure. It is found that of the two types having F-F bonds in the (001) plane, one identifies rather well with the 370-nm band and the other with the 320-nm band.
- Received 3 August 1966
DOI:https://doi.org/10.1103/PhysRev.153.1031
©1967 American Physical Society