EPR and optical absorption studies of VO 2+ doped l-arginine phosphate monohydrate single crystals — part I

Abstract

The electron paramagnetic resonance (EPR) studies on VO 2+ doped l-arginine phosphate monohydrate (LAP) single crystals at room temperature at X-band frequencies reveal the presence of two magnetically inequivalent VO 2+ sites occupying interstitial positions in the lattice with fixed orientations and show very high angular dependence. The principal values of the g and A tensors indicate that the electrostatic field around the VO 2+ ion is rhombic. The optical absorption spectra at room temperature show four absorption bands at 16 155, 14 775, 10 928 and 10 526 cm −1, characteristic of rhombic symmetry. From EPR and optical absorption data, the molecular orbital bonding coefficients ( β 2, ε 2, P and k) and the crystal field parameters have been evaluated.