Abstract
An analysis of the optical and magnetic properties of the (V(urea)6)3+ ion is given on the basis of the ligand field model. The hexaurea vanadium ion occupies a D3 site in the compound (V(urea)6)ClO4)3, and the threefold axis coincides with the axis of the crystal. The trigonal crystal field and spin-orbit interaction matrices, calculated using the 'strong field' wavefunctions, were diagonalized simultaneously with the corresponding matrices of the electrostatic and octahedral crystal field. The energy levels calculated in this way were fitted with the absorption spectrum and the strengths of various interactions were determined. The effective Hamiltonian for the ground (octahedral) term t22 3T1 was used to obtain an analytical expression for the magnetic susceptibility. The theoretical values of the magnetic susceptibility were compared with the experimental values in the temperature range 80-300 K. Since the trigonal crystal field parameters and the spin-orbit interaction parameter appear in the expression for the magnetic susceptibility and they also affect the energy levels, their values were obtained by fitting the theoretical results simultaneously to the optical and magnetic data available.