EPR of vanadyl impurity in zinc ammonium trihydrogen bis(orthophosphate) monohydrate single crystal

The electron paramagnetic resonance spectroscopic investigation of VO(II)-doped zinc ammonium trihydrogen bis(orthophosphate) monohydrate single crystal has been carried out at 300K. The single crystal, rotated along the three orthogonally crystallographic axes, have yielded spin Hamiltonian parameters g and A as: g(xx)=1.978, g(yy)=1.974, g(zz)=1.925 and A(xx)=7.4, A(yy)=7.8, A(zz)=19.4 mT. These spin Hamiltonian parameters reflect a slight deviation from axially symmetry to rhombic, which is elucidated by the interstitial occupation of the vanadyl ion. The isofrequency plots and EPR spectra at few orientations have been simulated using the calculated spin Hamiltonian parameters. The Fermi contact parameter (kappa) and dipolar interaction parameter (P) have been calculated as 0.857 and -128 x 10(-4)cm(-1), respectively. The percentage of metaloxygen bond has been identified as 20%.