title: Structural investigation and electron paramagnetic resonance of vanadyl doped alkali niobium borate glasses.
abstract: Glasses with compositions xNb(2)O(5).(30-x)M(2)O.69B(2)O(3) (where M=Li, Na, K; x=0, 4, 8 mol%) doped with 1 mol% V(2)O(5) have been prepared using normal melt quench technique. The IR transmission spectra of the glasses have been studied over the range 400-4000 cm(-1). The changes caused by the addition of Nb(2)O(5) on the structure of these glasses have been reported. The electron paramagnetic resonance spectra of VO(2+) ions in these glasses have been recorded in X-band (9.14 GHz) at room temperature (300 K). The spin Hamiltonian parameters, dipolar hyperfine coupling parameter and Fermi contact interaction parameter have been calculated. It is observed that the resultant resonance spectra contain hyperfine structures (hfs) due to V(4+) ions which exist as VO(2+) ions in octahedral coordination with a tetragonal compression in the present glasses. The tetragonality of V(4+)O(6) complex decreases with increasing concentration of Nb(2)O(5). The 3d(xy) orbit contracts with increase in Nb(2)O(5):M(2)O ratio. Values of the theoretical optical basicity, Lambda(th), have also been reported.
authors.affiliation: Department of Applied Physics, Guru Jambheshwar University of Science & Technology, Hisar, Haryana, India. aagju@yahoo.com
authors.forename: A
authors.initials: A
authors.lastname: Agarwal
authors.forename: A
authors.initials: A
authors.lastname: Sheoran
authors.forename: S
authors.initials: S
authors.lastname: Sanghi
authors.forename: V
authors.initials: V
authors.lastname: Bhatnagar
authors.forename: S K
authors.initials: SK
authors.lastname: Gupta
authors.forename: M
authors.initials: M
authors.lastname: Arora
mesh_terms: D001881:Borates / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D005898:Glass / Q000737:chemistry*; D009556:Niobium / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014638:Vanadates / Q000737:chemistry*
chemical_list: D001881:Borates; D009556:Niobium; D014638:Vanadates