ESR of V4+ions alpha cristobalite AlPO4

The X-band ESR spectrum of vanadium-doped alpha cristobalite AlPO 4 has been observed at room temperature. The spectrum, attributed to V 4+ in a distorted tetrahedral site, can be described by a spin Hamiltonian of axial symmetry. The Hamiltonian parameters are: g/sub ///=1.9168, g perpendicular to =1.9835, mod A/sub /// mod =188*10 -4 cm -1 , mod A perpendicular to mod =75*10 -4 cm -1 . The wavefunction of the ground state is of the d x2-y2 type.