Miao Di, Xu Yi-zhuang, Yang Jun, Xu Zhen-hua, Wu Jin-guang
College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2004 May;24(5):513-8.
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.
激发光谱通常用于研究荧光物质的分子结构与荧光过程中能量转移之间的关系。人们通常认为样品的激发光谱等同于其吸收光谱，甚至是后者的复制品。然而，在许多情况下都发现了例外。综合考虑影响溶液激发光谱的各种因素，建立了一个模型来研究激发光谱的行为。在对该模型进行数学分析，包括引入突变理论后，我们得出了以下结论：就拓扑性质而言，只要物质的浓度低于阈值，激发光谱就与其吸收光谱相同。然而，当浓度超过阈值时，激发光谱会经历一系列拓扑突变，导致与吸收光谱有显著偏差。对溶解在正己烷中的萘的激发光谱和吸收光谱进行的对比研究证实了上述假设。
