Sreenivasulu V, Upender G, Chandra Mouli V, Prasad M
Glassy Materials Research Laboratory (GMRL), Department of Physics, Osmania University, Hyderabad 500 007, Telangana, India.
Glassy Materials Research Laboratory (GMRL), Department of Physics, Osmania University, Hyderabad 500 007, Telangana, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2015 Sep 5;148:215-22. doi: 10.1016/j.saa.2015.03.085. Epub 2015 Apr 7.
The glasses with composition 64TeO2-15ZnO-(20-x)CdO-xBaO-1V2O5 (0⩽x⩽20 mol%) were prepared by conventional melt quenching technique. X-ray diffraction analysis was used to confirm the amorphous nature of the glasses. The optical absorption studies revealed that the cut-off wavelength (λα) decreases while optical band gap energy (Eopt) and Urbach energy (ΔE) values increase with an increase of BaO content. Refractive index (n) evaluated from Eopt was found to decrease with an increase of BaO content. The physical parameters such as density (ρ), molar volume (Vm), oxygen packing density (OPD), optical basicity (Λ), molar refraction (Rm), and metallization criterion (M) evaluated and discussed. FTIR and Raman spectroscopic studies showed that the glass network consists of TeO4, TeO3+1/TeO3 and ZnO4 units as basic structural units. The glass transition temperature (Tg) of glass sample, onset crystallization temperature (To) and thermal stability ΔT were determined from Differential Scanning Calorimetry (DSC). Using electron paramagnetic resonance (EPR) spectra of vanadium glasses the spin Hamiltonian parameters and dipolar hyperfine coupling parameters of VO(2+) ions were calculated. It was found that V(4+) ions in these glasses exist as VO(2+) in octahedral coordination with a tetragonal distortion and have C4V symmetry with ground state dxy. Tetragonality (Δg∥/Δg⊥) of vanadium ion sites exhibited non-linear variation with BaO content.
采用传统熔体淬冷技术制备了组成为64TeO₂-15ZnO-(20-x)CdO-xBaO-1V₂O₅（0⩽x⩽20摩尔%）的玻璃。利用X射线衍射分析确认了玻璃的非晶态性质。光学吸收研究表明，随着BaO含量的增加，截止波长（λα）减小，而光学带隙能量（Eopt）和乌尔巴赫能量（ΔE）值增加。由Eopt计算得到的折射率（n）随BaO含量的增加而降低。对密度（ρ）、摩尔体积（Vm）、氧堆积密度（OPD）、光学碱度（Λ）、摩尔折射度（Rm）和金属化判据（M）等物理参数进行了评估和讨论。傅里叶变换红外光谱（FTIR）和拉曼光谱研究表明，玻璃网络由TeO₄、TeO₃⁺¹/TeO₃和ZnO₄单元作为基本结构单元组成。通过差示扫描量热法（DSC）测定了玻璃样品的玻璃转变温度（Tg）、起始结晶温度（To）和热稳定性ΔT。利用钒玻璃的电子顺磁共振（EPR）光谱计算了VO(2+)离子的自旋哈密顿参数和偶极超精细耦合参数。发现这些玻璃中的V(4+)离子以八面体配位的VO(2+)形式存在，具有四方畸变，基态为dxy，具有C4V对称性。钒离子位点的四方度（Δg∥/Δg⊥）随BaO含量呈非线性变化。
