Radiation Damage Studies of Co²⁺ and Ni²⁺ Doped NH<inf>4</inf>Cl Crystals

Results from the radiation damage studies of NH4Cl:Co2+ and NH4Cl:Ni2+ crystals are presented. On X‐irradiation at room temperature the NH4Cl:Co2+ crystals are found to absorb at 270, 345, 585, 900, and 1000 nm. These absorption bands are attributed to the charge transfer transitions between radiation induced hydrazine‐like defect, N2H 4+, and ligands H2O or NH3 which are made available in the crystal along with the divalent impurity. If not all the absorption bands but similar absorption is found on irradiation in Ni2+ doped NH4Cl crystals also. ESR studies of X‐rayed Ni2+ doped NH4Cl crystals reveal the formation of both, Ni+ and Ni3+. Spin‐Hamiltonian parameters for these centers are given. Copyright © 1983 WILEY‐VCH Verlag GmbH & Co. KGaA