Theoretical investigations on the EPR parameters and local structures for V4+ in alkali niobium borate glasses
| Autor: | Zhen-Ya Zhang, Xiao-Yu Li, Qin-Sheng Zhu, Shao-Yi Wu, Gui-Jun Chen, Qing Zhang |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
010302 applied physics
Force constant Materials science Analytical chemistry Niobium chemistry.chemical_element Vanadium 02 engineering and technology 021001 nanoscience & nanotechnology Condensed Matter Physics Alkali metal 01 natural sciences Electronic Optical and Magnetic Materials law.invention Tetragonal crystal system Octahedron chemistry law 0103 physical sciences Materials Chemistry Ceramics and Composites 0210 nano-technology Boron Electron paramagnetic resonance |
| Zdroj: | Journal of Non-Crystalline Solids. 522:119559 |
| ISSN: | 0022-3093 |
| DOI: | 10.1016/j.jnoncrysol.2019.119559 |
| Popis: | EPR parameters and local structures for V4+ in xNb2O5•(30-x)A2O•69B2O3 (NAB, where A = Li, Na, K; x = 0, 4, 8 mol%) glasses are theoretically studied using the perturbation formulas of EPR parameters for tetragonally compressed octahedral 3d1 clusters. From the quasi-linear concentration variations for covalency factor N, tetragonal compression ratio ρ and core polarization constant κ with only three adjustable coefficients, the concentration dependences of EPR parameters are suitably interpreted. N increases linearly for NLB (0.839–0.864) and NNB (0.801–0.811) with x (0–8 mol%) but shows the quadratic decrease for NKB (0.802, 0.807, 0.801 at 0, 4 and 8 mol%), whereas ρ and κ decrease linearly. For different alkali metal A at the same x, N decreases with increasing ionicity of A, while ρ and κ increase due to declining force constant of V4+–O2– bond and enhancing vanadium 3d-3 s (4 s) orbital admixtures, respectively. |
| Databáze: | OpenAIRE |
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