Nickel centers in strontium tartrate tetrahydrate single crystals

Optical absorption of Ni2+ doped in strontium tartrate tetrahydrate (SrTr.4H2O) has been studied at room temperature (300 K) and at liquid nitrogen temperature (80 K). Polarised absorption studies along the three crystallographic axes have also been carried out. The spectrum shows the characteristic features of Ni2+ in a distorted octahedral field. A good fit between calculated and experimental band positions has been obtained. The crystal field parameters Dq, B and C are calculated by using the energy matrices and energy equations (Dq = 850 cm-1, B = 930 cm-1 and C = 4000 cm-1) and the crystal field transitions are assigned. A correlation of the ESR and observed changes in optical absorption spectra after irradiation indicates the formation of Ni3+. © 1983.