F-Centers and Oxygen-Interstitials in MgO

Abstract

ABSTRACTMgO single crystals have been irradiated at different temperatures (4 K, 300 K) with electrons of energies varying between 0.3 and 3 MeV. The irradiation induced defects and their reactions during thermal annealing have been investigated by optical absorption spectroscopy and by X-ray diffraction. The relaxation volume (Viel ≈ 1 at.vol. = a3/8) and the migration energy of the interstitial atoms (≈ 1.6 eV) are determined and an ionization induced and thermally assisted migration process is observed for the first time. The relevance of these results for the understanding of the cascade damage observed after neutron- or ion-damage is discussed.