Optical vibronic absorption spectra in 14.8 MeV neutron damaged sapphire

Abstract Preliminary observations of several anisotropic optical absorption bands are reported for high-purity sapphire following exposure to a pure 14.8 MeV neutron beam. These bands are compared with and found to be similar to those reported following fission-spectrum exposure, and are associated with lattice displacement damage. Two of these bands at 3.47 and 4.09 eV show similar sharpline features at low temperature; this ≈200 cm −1 vibronic progression it tentatively associated with a local mode.