 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Electron Spin Resonance (ESR) and Optical Absorption Spectra of a Manganese Doped Soda-Lime-Silicate Glass System) ผู้เขียน: Nattapon Srisittipokakun, Chittra KedKaew, Jakrapong Kaewkhao, Treedej Kittiauchawal, เขมฤทัย ถามะพัฒน์, พิเชษฐ ลิ้มสุวรรณ สื่อสิ่งพิมพ์:pdf AbstractA (65-x)SiO2:10CaO:25Na2O:xMnO2 glass system with 0 ? x ? 0.5 mol% was prepared and investigated by X-ray diffraction, optical absorption and ESR spectroscopies. The XRD pattern of undoped glass confirmed the formation of an amorphous vitreous structure. The optical absorption spectra exhibited a predominant broad band around 500 nm and its increase was clearly observed from 0.1 mol% of MnO2. This band corresponded to an allowed transition from 5Eg5T2g, of Mn3+ ions. When the MnO2 concentration was increased, the absorption band due to Mn3+ ions dominated. The ESR spectra results exhibited resonance signals at g ? 2.0 with a sextet of hyperfine lines and less intensity at g ? 4.3. The group of hyperfine lines at g ? 2.0 represented Mn2+ ions in octahedral symmetry. However, these lines were broader and disappeared for higher MnO2 concentrations. This behavior indicated the reduction of Mn2+ ions in the glass system as the concentration of MnO2 was increased by increasing the Mn3+ ions. |