University Science Instrumentation Center, Sri Venkateswara University, Tirupati, India.
J Phys Chem A. 2012 Apr 12;116(14):3547-55. doi: 10.1021/jp210398k. Epub 2012 Mar 28.
Electron paramagnetic resonance (EPR), optical absorption, and FT-IR spectra of vanadyl ions in the sodium-lead borophosphate (Na(2)O-PbO-B(2)O(3)-P(2)O(5)) (SLBP) glass system have been studied. EPR spectra of all the glass samples exhibit resonance signals characteristic of VO(2+) ions. The spin Hamiltonian parameters g and A are found to be independent of the V(2)O(5) content and temperature. The values of the spin Hamiltonian parameters indicate that the VO(2+) ions in SLBP glasses are present in octahedral sites with tetragonal compression. The population difference between Zeeman levels (N) is calculated as a function of temperature for an SLBP glass sample containing 1.0 mol % VO(2+) ions. From the EPR data, the paramagnetic susceptibility (χ) is calculated at different temperatures, and the Curie constant (C) is calculated from the 1/χ versus T graph. The optical absorption spectra of the glass samples show two absorption bands, and they are attributed to V(3+) and V(4+) ions. The optical band gap energy (E(opt)) and Urbach energy (ΔE) are calculated from their ultraviolet absorption edges. It is observed that, as the vanadium ion concentration increases, E(opt) decreases and ΔE increases. The study of the IR absorption spectrum depicts the presence of BO(3), BO(4), PO(3), PO(4), and VO(5) structural units.
电子顺磁共振（EPR）、光学吸收和钒氧离子在钠-铅硼磷酸盐（Na(2)O-PbO-B(2)O(3)-P(2)O(5))（SLBP）玻璃系统中的傅里叶变换红外（FT-IR）光谱已被研究。所有玻璃样品的 EPR 光谱都表现出 VO(2+) 离子的特征共振信号。自旋哈密顿参数 g 和 A 被发现与 V(2)O(5) 含量和温度无关。自旋哈密顿参数的值表明，SLBP 玻璃中的 VO(2+) 离子存在于具有四面体压缩的八面体位置。作为 SLBP 玻璃样品中 1.0 mol % VO(2+) 离子的函数，计算了温区之间的塞曼能级（Zeeman levels）（N）的差分。根据 EPR 数据，在不同温度下计算顺磁磁化率（χ），并从 1/χ 与 T 的关系图计算居里常数（C）。玻璃样品的光学吸收光谱显示出两个吸收带，它们归因于 V(3+) 和 V(4+) 离子。从其紫外吸收边缘计算出光学带隙能（E(opt)）和 Urbach 能（ΔE）。观察到，随着钒离子浓度的增加，E(opt) 减小而 ΔE 增加。IR 吸收光谱的研究描绘了 BO(3)、BO(4)、PO(3)、PO(4) 和 VO(5) 结构单元的存在。
