Molecular Triplet State Properties and Processes

在这项由化学部实验物理化学计划支持的项目中，魏斯曼将研究气相和溶液相分子三重态光谱的动力学和光物理。气相研究将把对三重态碰撞动力学的研究扩展到嘧啶、吡啶、均三氮和萘，以了解三重态寿命与过剩能量的关系。将使用时间分辨光学吸收光谱来收集数据。这些数据将使用主方程模拟进行分析，以提供更容易与理论计算相比较的结果。我们将使用瞬时吸收、光声和发射光谱测量来研究溶液相富勒烯三重态分子的能量学和动力学。要研究的分子包括C60、C70和更高的富勒烯。这些结果将形成一个光物理性质的数据库，以了解这些化合物的激发态行为，并计划和优化潜在的富勒烯应用。多原子分子的三重态是重要的研究，因为这些分子通常比分子的其他激发态持续更长时间，同时显示出化学反应、电子转移和能量转移的增加趋势。分子所处的激发态的一致性也可以决定或改变感兴趣的特定化学反应的进程或效率。该项目的研究具有基础性的意义，但也可能影响实际应用，例如使用富勒烯衍生化合物的光学数据存储系统。

In this project supported by the Experimental Physical Chemistry Program of the Chemistry Division, Weisman will investigate the dynamics and photophysics of triplet spectroscopic states of both gas-phase and solution-phase molecules. The gas-phase studies will extend investigations of triplet collision dynamics to pyrimidine, pyridine, sym-triazine, and naphthalene in order to understand the dependence of triplet-state lifetime on excess energy. Time-resolved optical absorption spectroscopy will be used to gather data. These data will be analyzed using Master Equation simulations to provide results that can be more easily compared with theoretical calculations. The energetics and dynamics of solution-phase fullerene triplet-state molecules will be examined using transient absorption, photoacoustic, and emission spectroscopic measurements. Molecules to be studied include C60, C70, and higher fullerenes. The results will form a data base of photophysical properties for understanding excited-state behavior in these compounds and for planning and optimizing potential fullerene applications.Triplet states of polyatomic molecules are important to investigate because such molecules typically persist much longer than the molecule's other excited states while displaying increased tendencies for chemical reaction, electron transfer, and energy transfer. The identity of the excited state that a molecule can find itself in can also determine or alter the course or efficiency of a particular chemical reaction of interest. The studies in this project are of fundamental interest, but they can also impact practical applications, such as optical data storage systems using fullerene-derived compounds.