荧光激发光谱的突变行为研究  

Saltation Behavior in Excitation Spectra of Fluorescent Molecules

作　　者：苗笛[1] 徐怡庄[1] 杨军[1] 许振华[1] 吴瑾光[1] 

机构地区：[1]北京大学化学与分子工程学院,北京100871

出　　处：《光谱学与光谱分析》2004年第5期513-518,共6页Spectroscopy and Spectral Analysis

基　　金：国家重点基础研究发展规划项目(G1998061307);国家自然科学基金(50203001;29671002;39730160;20023005);国家科委"极端条件下物质的标准"(2001deA20023B);稀土材料化学国家重点实验室主任基金资助项目

摘　　要：在研究荧光物质的荧光光谱时 ,人们利用激发光谱探讨荧光发射过程中的能量传递与荧光物质分子结构之间的关系。一般认为 ,激发光谱和吸收光谱有着对应的关系 ,甚至是吸收光谱的复制。但是 ,例外却是很多。综合考虑了在传统的测量条件下影响激发光谱的各种因素 ,建立了溶液中荧光物质激发光谱的数学模型 ,并结合突变论的思想对模型加以数学分析。结果表明 ,当样品浓度低于某一浓度上限时 ,样品的激发光谱与吸收光谱具有相同的拓扑结构。但是随着样品浓度的升高 ,激发光谱谱带的拓扑结构会发生一系列的突变的现象。最终导致荧光样品的激发光谱与吸收光谱之间存在很大差异。通过对萘的正己烷溶液荧光激发光谱和吸收光谱进行比较研究 ,从实验上证实了上述理论分析结果的正确性。在传统的测量条件下 ,只有当样品的浓度处于某一极限浓度以下时 ,样品的激发光谱与吸收光谱之间是拓扑等价的。超过这一浓度 ,这种等价关系不再成立。Excitation spectra are commonly used to study relationship between molecular structure of fluorescent substances and energy transfer during the fluorescence process. It is generally taken for granted that the excitation spectrum of the sample is equivalent to its absorption spectrum, even a copy of the latter. However, exceptions have been found in many cases. Considering various factors that affect the excitation spectra of solution comprehensively, a model has been established to study the behavior of the excitation spectra. After analyzing the model mathematically, including introducing catastrophe theory, we came into the following conclusions: As far as the topological properties are concerned, the excitation spectra are the same as its absorption spectra, provided the concentration of the substance is below a threshold. However, when the concentration is beyond the threshold, the excitation spectra undergo a series of topological saltation, leading to significant a deviation from the absorption spectra. Comparative studies of both excitation and absorption spectra of naphthalene dissolved in n-hexane confirmed the above hypothesis.

关 键 词：荧光激发光谱 突变行为 吸收光谱 拓扑结构 样品浓度 

分 类 号：O657.33[理学—分析化学]