ESR of copper-doped sodium citrate

Single crystal ESR spectra of Cu2+ ion doped in sodium citrate are reported at room temperature. The observed spectra are fitted to a spin-Hamiltonian of rhombic symmetry with g(x) = 2.1076 +/- 0.002, g(y) = 2,1289 +/- 0.002, g(z) = 2.4454 +/- 0.002, A(x) = (40 +/- 2) 10(-4) cm(-1), A(y) = (62 +/- 2)10(-4) cm(-1) and A(z) = (78 +/- 2)10(-4) cm(-1). It is found that Cu2+ enters the lattice as a substitutional impurity replacing an Na+ ion. The ground state wave function of Cu2+ ion in this lattice is also determined from the spin-Hamiltonian constants obtained from ESR results. It is found that the ground state is predominantly vertical bar x(2) - y(2)). With the help of the optical absorption study, the nature of bonding in the complex has also been discussed. (c) 2005 Elsevier B.V. All rights reserved.