C_(60)在几种溶剂中紫外吸光度的负热效应  

The Negative Temperature Effect of UV Absorbance on C_(60) in Different Solvents

作　　者：杨涛[1] 曾繁清[1] 葛琦[1] 熊谦[1] 郭峰[1] 张勋高[2] 

机构地区：[1]武汉大学电子信息学院测控技术与仪器系,湖北武汉430072 [2]武汉大学分析测试中心,湖北武汉430072

出　　处：《光谱学与光谱分析》2004年第2期180-182,共3页Spectroscopy and Spectral Analysis

基　　金：国防预研基金资助项目

摘　　要：所采用的变温光谱差减方法是将待测试样分成两份 ,一份作为参比试样 ,恒定在某一温度 (参比温度 )下 ,另一份作为待测样品 ,选定另一待观测温度 ,在一定的波长范围内 ,用岛津UV 2 4 0型紫外 可见双光束分光光度计扫描 ,获得紫外吸收温差光谱 (UVSDT)。选择不同的温度差 ,测得温差光谱随温差的变化。观测了C60 分子在乙醇、环己烷、正己烷、异丙醇等几种有机溶剂中吸光度随温度的变化。观测结果发现C60 溶液的吸光度变化存在显著的负温度效应。C60 的UV吸收光谱峰随试样温度升高而降低 ,UV吸收温差光谱 (U VSDT)为负峰 ,UVSDT峰强随温差增大而负向增大。说明C60 的结构对温度有较强的依赖关系。这种依赖关系与π π 电子跃迁类型密切相关。实时现场测量C60 溶液的吸光度随温度变化规律 ,对分离、纯化、分析富勒烯 ,认识C60 特性、研究以溶剂为媒介的化学反应机理 ,以及提高测量的准确度和重现性等 。Ultraviolet Absorption Spectrum of Difference in Temperature(UVSDT) of C 60 was studied in different solvents by UV 240 ultraviolet visible spectrophotometer. Two samples were tested, one of which acted as reference sample and the other as ready test sample. During the period of the experiment, the temperature of the reference sample remained constant, while that of the ready test sample was changed to obtain difference in temperature. The two samples were scanned in succession by UV 240 ultraviolet visible spectrophotometer using a certain range of wavelength. By changing the temperature of the ready test sample, we can get the ultraviolet absorption spectrum changing curve with temperature differential. In addition, the curve was studied by putting C 60 in different solvents(alcohol, cyclohexane, n hexane and 2 propanol). The curve indicates that the intensity of the absorption peak wavelength of C 60 decreased with increasing the temperature of the sample, and a negative peak was observed in UVSDT. And the greater the difference in temperature, the higher the intensity of the negative peak. The result reflects that the structure of C 60 depends strongly on its temperature, and the dependent relationship is closely related to the type of π π * electron transition. So it's valuable to test the absorption rate of C 60 and obtain the changing curve in real time. It'll help us to separate, purify, analyze, and characterize C 60 . And it'll also help to do research on the mechanism of the chemical reactions, which take place in solvents, as well as to improve veracity.

关 键 词：碳60 紫外吸光度 负热效应 变温光谱差减方法 紫外吸收温差光谱 有机溶剂 富勒烯 温度 

分 类 号：O635.1[理学—高分子化学]