Vibronic photoexcitation spectra of irradiated spinel MgOAl2O3(n=2) at low temperatures

vibronic photoexcitation band at approximately 230 nm was found at 13 K in reactor neutron- and electron-irradiated magnesiumaluminate spinel ( MgOAl2O3). Vibronic structure was found to be temperature dependent and became obscure at over 120K. Huang Rhys factor S and Debye Temperature D were estimated from the temperature dependence of the 230 nm band bycurve-fitting method using Debye approximation. Origin of the vibronic photoexcitation band was suggested as F center.