EPR and optical absorption studies of Cu2+ ions doped magnesium citrate decahydrate single crystals

X-band electron paramagnetic resonance (EPR) studies of Cu2+ ions in magnesium citrate decahydrate single crystals are done at room temperature. Detailed EPR analysis indicates the presence of only one Cu2+ site. Cu2+ is found to take up substitutional position at Mg site. The angular variation of the EPR spectra in three planes a*b, bc and ca* are used to determine principal g and A tensors. The spin Hamiltonian parameters are: gx = 2.0346, gy = 2.1400, gz = 2.3874, Ax = 57, Ay = 76, Az = 99 (×10−4) cm−1. The optical absorption study is also carried out at room temperature and absorption bands are assigned to various transitions. The theoretical band positions are estimated using energy expressions and a good agreement is obtained with the experimental values. By correlating EPR and optical data, different molecular orbital coefficients are evaluated and the nature of bonding in the complex is discussed.