【摘要】 采用X射线荧光光谱(XRF)、紫外可见光光谱(UV-Vis)、红外光谱(FT-IR)和拉曼光谱(RM)多种光谱学分析方法对天然与合成紫晶样品进行测试。XRF结果显示,天然与合成紫晶的成分均为w=99%SiO2,分别含有致色的Fe元素和其他微量金属杂质;红外光谱图显示天然紫晶在3 560~3 200 cm-1区间内有一强宽吸收带,合成紫晶在3 600~3 000 cm-1区间内有2个较尖锐的水吸收峰,分别位于3 583 cm-1和3 421 cm-1;拉曼光谱图显示,天然紫晶缺失401 cm-1和1 161 cm-1拉曼位移。紫外可见光光谱显示,天然与合成紫晶的致色机理相同,均为空穴色心致色,350 nm吸收峰和540 nm吸收带的吸收分别对应于t1→t*2和t1→a*的电子跃迁。通过在空气中不同温度下的热处理实验,发现紫晶空穴色心在400℃附近消失。更多还原

【Abstract】 In the present work,several spectroscopy analytic methods are applied for testing natural and synthetic amethyst samples,including X-ray fluorescence spectroscopy(XRF),ultraviolet-visible spectroscopy(UV-Vis),FT-infrared spectroscopy(FT-IR) and Raman spectroscopy(RM).XRF analysis results exhibit that the components of both natural and synthetic amethyst samples contain 99% silica and impurities,such as coloration element Fe and other trace metal elements.FT-IR spectra show that natural amethyst samples have a strong and broad absorption band in the 3 560-3 200 cm-1 range,while synthetic amethyst samples have two sharp water absorption bands,which locate in 3 583 cm-1 and 3 421 cm-1,respectively.RM spectra of the natural amethyst sample show the lack of 401 cm-1 and 1 161 cm-1 Raman shift.UV-Vis spectra show that coloration of natural and synthetic amethyst samples has the same mechanism,both caused by hole color centers,corresponding to 350 nm and 540 nm absorption bands due to the electronic transition of t1→t*2 and t1→a*,respectively.Heat treatment experiments at different temperatures in the air show that the color centers of amethyst disappear near 400 ℃.更多还原