期刊
JOURNAL OF ALLOYS AND COMPOUNDS
卷 574, 期 -, 页码 391-397出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.jallcom.2013.05.177
关键词
Borate glasses; Transition metal; Halides; Optical basicity; Ligand field theory; Optical band gap and tails energies
Borate oxide glass system of composition 10 KM-64.7 B2O3-25 Na2O-0.3 Cr2O3 (M = Cl, Br and I) was prepared by conventional melt quenching technique. The amorphous nature of the investigated glasses was checked by the X-ray diffraction (XRD) technique. The optical basicity of the system has been calculated, and was found to increase by going from KCl to KBr and to KI. Optical absorption spectra were recorded in the UV-visible range. Through a careful analysis of the data, the ligand field parameters (crystal field strength Dq, Racah parameters B and nephelauxetic functions h) and the optical parameters (optical band gap, Urbach tail band width, and refractive index) have been estimated. The obtained results reveal a strong correlation between that ligand field parameters and the type of halogen atom; the crystal-field strength of KCl or KBr samples are very pronounced but it is rather weak in the KI sample. Electron spin resonance (ESR) has been used to probe the valency of the Chromium ions. The resulting ESR parameters revealed that chromium ions are predominantly in the trivalent state with traces of hexavalent state. Using Infrared spectroscopy (IR) information on the boron structural units has been obtained. The N-4 ratio increases by replacing the KCl by KBr or KI, and it was found that the tetrahedral coordination of Cr+ ions becomes preferential in the host glasses with increasing the optical basicity. (C) 2013 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据