Electron Paramagnetic Resonance and Optical Absorption Spectra of V 0 2 + in CsCl Single Crystals

In vanadium-doped CsCl crystals grown from aqueous solutions anisotropic EPR spectra due to V0 are observed and analyzed at room temperature. Evidence is presented that isotropic spectra of this ion observed in this and other compounds are due to inclusions of growth solution and not to rapid rotation of the vanadyl ion in the solid as normally assumed. At 77 K a well resolved vibrational progression of about 820 cm 1 is observed in the first ligand field band of this ion. The optical absorption spectra indicate the presence of a second valence state of vanadium, most likely V, in varying proportions depending on the crystal growth temperature.