Single Crystal EPR and Optical Studies of VO (II) Ion Doped in Triglycine Acetate

- Electron paramagnetic resonance studies on single crystals of Triglycine acetate doped with VO (II) are carried out in the room temperature at X-band frequencies. Single crystal rotation in each of the three mutually orthogonal crystallographic planes namely ab, ac* and bc* indicate two chemically equivalent sites, with differing intensities. Angular variation studies in all the three orthogonal planes confirm that the two intense vanadyl sites referred as I and II, are found to be magnetically inequivalent, have occupied interstitial positions in the lattice. The spin Hamiltonian parameters obtained for the two sites are Site I gxx=1.9818, gyy=1.9646, gzz=1.9346, Axx=7.295 mT, Ayy=6.396 mT, Azz= 18.456 mT. Site II gxx=1.9815, gyy=1.9713, gzz=1.9348, Axx=5.609 mT, Ayy= 7.140 mT, Azz =17.942 mT. However the analysis of the powder spectrum reveals the presence of only one site. Admixture coefficients, Fermi contact and dipolar interaction terms have also been evaluated. UV-Visible data of doped complex confirm the structure and symmetry of the host lattice.