Electron spin resonance studies of VO²⁺ in NH₄Cl single crystals

Abstract

Electron spin resonance studies of VO²⁺ in ammonium chloride single crystals have been reported for the first time. Room temperature studies reveal, that there is a very fast re-adjustment of VO²⁺ molecular ion, in the crystal, giving rise to an isotropic spectrum with spin Hamiltonian constants g = 1·966 ± 0·001 and A = (103·9 ± 0·9) × 10⁻⁴cm⁻¹. At a low temperature corresponding to the ordered cubic phase of the host lattice, an anisotropic spectrum is obtained with spin Hamiltonian constants: g ⊥ = 1 ·925 ± 0·005 g⊥1·977 ± 0·002 A = (174·0 ± 0·9) × 10⁻⁴ cm⁻¹ B = (67·8±0 · 9) × 10⁻⁴ cm⁻¹