Franck-Condon Active Intermolecular Vibrations in Condensed Phases

罗切斯特大学的Anne Myers得到了实验物理化学项目的支持，在她的继续研究中，她使用共振拉曼和荧光光谱来表征在液体和非晶固体的周围环境中发色团的电子跃迁与核自由度的耦合。将进行三种类型的实验：(i)分子离子的拉曼线宽将在共振和非共振激励条件下进行比较，以验证先前观察到的共振线宽增加是由于发色团局域振动与溶剂或分子间声子耦合所致的假设；（ii）将测量共振激发发射光谱作为温度的函数，并对光谱进行建模以更好地理解温度依赖性；（iii）在色团/矩阵组合中测量低温荧光线窄化光谱，以研究耦合声子频率和耦合强度对色团的依赖性。这些研究将对导致凝聚态介质中电子吸收扩大的过程和影响凝聚态化学反应速率的过程提供见解。基于固体中持续光谱孔燃烧的实用光存储器件的开发将受益于本研究的更好理解。

Anne Myers of the University of Rochester is supported by the Experimental Physical Chemistry Program in her continuing studies in which she uses resonance Raman and fluorescence spectroscopies to characterize the coupling of electronic transitions of a chromophore to nuclear degrees of freedom in the surrounding environment in liquids and amorphous solids. Three types of experiments will be carried out: (i) Raman linewidths for molecular ions will be compared under resonant vs. nonresonant excitation conditions to test the hypothesis that the previously observed increase in linewidth on resonance is due to coupling of the chromophore-localized vibrations to solvent or intermolecular phonons; (ii) resonantly excited emission spectra will be measured as a function of temperature and the spectra will be modeled to better understand the temperature dependence; (iii) low-temperature fluorescence line-narrowing spectra will be measured in chromophore/matrix combinations to investigate the chromophore dependence of the coupled phonon frequencies and coupling strengths. These investigations will provide insight to the processes that are responsible for the broadening of electronic absorptions in condensed media and to processes that affect chemical reaction rates in condensed phases. Efforts to develop practical optical memory devices based on persistent spectral hole burning in solids will be aided by a better understanding resulting from this research.