ESR Spectra of ZnSiF6·6H2O:Ni2+ in a Parallel and Perpendicular Configuration

The ESR spectra of ZnSiF₆·6H₂O:Ni²⁺ obtained with rf and dc magnetic fields parallel as well as perpendicular are studied for several crystal orientations. Experimental line positions and relative intensities are compared with those calculated by a numerical diagonalization of the spin Hamiltonian. The parameters of the spin Hamiltonian are found to be $\text{D\hspace{0.17em}=\hspace{0.17em}1838\hspace{0.17em}±\hspace{0.17em}15}\mathrm{G}$ and $\text{g\hspace{0.17em}=\hspace{0.17em}2.23\hspace{0.17em}±\hspace{0.17em}0.01}$ , with $g$ isotropic.