An EPR characterization of vanadium in CaO and Na2O based Al2O3–SiO2 glasses

Farah, Humera

doi:10.1016/j.jallcom.2006.11.135

Cited by 6 publications

(4 citation statements)

References 16 publications

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“…|ψ + and |ψ − express the two full configuration eigenfunctions of eigenstates 2 B 2 . A and A ⊥ are the parallel and perpendicular components of hyperfine tensor, and can be expressed as [9,10] …”

Section: Cdm Methodsmentioning

confidence: 99%

Investigations of the electron paramagnetic resonance spectra of VO2+ in CaO-Al2O3-SiO2 system

Wei

Zhang

et al. 2009

Pramana - J Phys

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The EPR spectra for VO 2+ in CaO-Al2O3-SiO2 system are calculated using complete diagonalization method (CDM) and perturbation theory method (PTM). The calculated results are in good agreement with the observed values. By comparing the calculated results by CDM and PTM in a wide range of crystal field parameters, the validity of the PTM formulas has been studied. It is shown that, the PTM formulas are reasonable and reliable in a wide range of CF parameters.

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Section: Cdm Methodsmentioning

confidence: 99%

Investigations of the electron paramagnetic resonance spectra of VO2+ in CaO-Al2O3-SiO2 system

Wei

Zhang

et al. 2009

Pramana - J Phys

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“…The values of the ratio (Δg // /Δg ⊥ ) for the SbPO 4 -GeO 2 glasses, where Δg // = (g || -g e ) and Δg ⊥ = (g ⊥ -g e ), are also included in Table 3. This ratio is a measure of the degree of tetragonal distortion of the VO 2+ sites [47,48]. It should be noted that the magnitude of the Fermicontact interaction can also be used to estimate the tetragonality of the VO 2+ site [27].…”

Section: H G βH S G β H S H S a I S A I S I Smentioning

confidence: 99%

Synthesis and structural characterization of a new SbPO4-GeO2 glass system

Montesso

Manzani

Donoso

et al. 2018

Journal of Non-Crystalline Solids

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This work presents the production and characterization of a new prolific binary glass system based on SbPO 4-GeO 2. The dependence of GeO 2 content on thermal, structural and optical properties were investigated by means of thermal analysis, Raman, UV-Vis-NIR, infrared, M-lines and EPR spectroscopy. Glass transition temperatures remain constant around 410°C when GeO 2 content is increased, indicating that GeO 4 units are not responsible for increasing the connectivity of PO 4 units. Thermal stability linearly increases as a function of GeO 2 content, reaching a value around 400°C for glass containing 90 mol% of GeO 2. Raman spectroscopy was used to evaluate the glass structural changes when GeO 2 is incorporated from 30 to 90 mol% indicating a gradual change from a phosphate to a germanate glass skeleton. The optical window extends from 350 nm at UV region, up to 2.7 μm in the middle-infrared region limited by the multiphonon cutoff due to the strong OH absorption. M-lines technique shows that increasing GeO 2 content decreases the refractive index, mainly because the lower concentration of higher polarizable antimony atoms. EPR spectra of heat treated V 2 O 5 doped glasses, at different temperatures above the glass transition temperature, shows the characteristic eight-line hyperfine splitting spectrum. The spin Hamiltonian parameters obtained from the simulated spectra indicates that the paramagnetic tetravalent vanadium ions in the glasses exist as vanadyl form VO 2+ , located in axially distorted octahedral sites. For glasses treated at higher temperatures a second VO 2+ component appears in the EPR spectra and the analysis of the spin-Hamiltonian parameters suggests that these vanadyl ions are in more tetragonal distorted octahedral sites than those in the glass.

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“…The perpendicular band is formed by six peaks. When the number of free O −2 ions or non-bridging oxygen ions was low, VO +2 ions tend to become more distorted [36,37] and can be transformed into V +5 O 2 + vanadyl species. The octahedral geometry of VO +2 is compressed due to the strong V +4 -O axial bonding which is outside the network.…”

Section: Esr Spectroscopymentioning

confidence: 99%