EPR and Optical Absorption Studies of VO2+Doped Trisodium Citrate Dihydrate Single Crystals

Abstract

The electron paramagnetic resonance of VO2+doped trisodium citrate dihydrate (Na3CgH5O7-2H2O) single crystals and powder has been examined at room temperature. The angular variation of the EPR spectra has shown that two different VO2+complexes are located in different chemical environments, each environment containing two magnetically inequivalent VO2+sites in distinct orientations occupying substitutional positions in the lattice and showing a very large angular dependence. The crystalline field around the VO2+ion is nearly axial. The optical absorption spectrum shows three bands, centered at 24631, 16892, and 12195 cm-1. The spin Hamiltonian parameters and the molecular orbital coefficients are calculated from the EPR and optical data, and result are discussed. © 2005, Verlag der Zeitschrift für Naturforschung. All rights reserved.