ESR of vanadyl ions in borate glasses

Abstract

Electron spin resonance (ESR) of VO 2+ in Li 2 O·RO·B 2 O 3 (where R = Ba, Ca and Mg) glasses have been studied. Spin Hamiltonian parameters, the dipolar hyperfine coupling parameter, and the Fermi contact interaction parameter have been calculated. It is observed that with a decrease in B 2 O 3 mol% there is an improvement in the octahedral symmetry of the V 4+ site. The theoretical value of optical basicity, Λ th , of these glasses has also been calculated. It is found that at constant mol% of Li 2 O there is a decreasc in A ∥ , A ⊥ and Δ g ∥ /Δ g ⊥ and an increase in P with increase in the value of Λ th , whereas at constant mol% of B 2 O 3 by varying modifier contents the spin Hamiltonian parameters are independent of Λ th .