Abstract
Ultraviolet optical absorption, emission, and excitation spectra are presented for 14-MeV neutron-irradiated high-purity crystalline . Low-temperature polarized excitation spectra for the 3.8-eV luminescence correlated well with polarized absorption at 4.8 eV (both polarizations) and 5.4 eV (). These optical properties compare favorably with those predicted using wave functions from an earlier pointion calculation for the center by La, Bartram, and Cox. The 4.8- and 5.4-eV absorption bands are assigned to the and transitions, respectively, of the center and the 3.8-eV luminescence is assigned to the transition. The transition could not be conclusively identified, but preliminary evidence suggests it occurs near 6.3 eV. Similar absorption and emission bands are observed following energetic-proton and bombardment. Other uv optical properties are presented, including the quantum efficiency, lifetime, and temperature dependence of the emission.
- Received 12 June 1978
DOI:https://doi.org/10.1103/PhysRevB.18.7089
©1978 American Physical Society