RUI: Spectroscopic and Computational Studies of Alpha, Beta-Unsaturated Carbonyl Compounds in Triplet Excited States

威斯康星大学Eau Claire分校化学系的Stephen Drucker教授是由化学结构、动力学和机制A(CSDM-A)计划资助的，该计划的目的是“三重态激发态中α，β-不饱和羰基化合物的光谱和计算研究”。三重态(具有两个未配对电子的物种)在光存在下发生的许多反应中发挥着核心作用。德鲁克教授和他的团队正在研究一系列有机分子三重态的本质，并探索三重态与其单重态(没有未配对电子的物种)之间的差异。这些研究为光诱导的化学反应提供了基本的见解。此外，这些实验还为测试或改进化学物种的计算处理提供了基准光谱信息。在这个项目中，本科生小组成员将进行深入的研究。这样的机会为本科教育项目增加了实质性的价值，也可以培养丰富的深造机会。与普渡大学研究人员的持续合作将使德鲁克教授的本科生能够参与一系列活动。反过来，合作研究小组的研究生将能够在与德鲁克教授和他来自密歇根大学Eau Claire的学生互动时探索本科机构的教师职业生涯。使用狭缝喷嘴源记录了丙烯醛和同位素取代衍生物在自由喷射膨胀冷却条件下的腔振铃(CRD)光谱。这些实验提供了高精度的惯性常数，将被用来确定T1态的替代结构。实验几何参数将与从高级计算中预测的平衡几何参数进行比较。在该项目的第二个组成部分中，在室温或平面自由喷射膨胀中的CRD被用来表征单环α，β不饱和羰基化合物的最低三重态。对环烯酮，包括环内酯的研究，提供了关于三重态(n，pi*)和(pi，pi*)的相对能量，构型混合的倾向，以及这些分子之间的超共轭的信息。再现这种差异的能力将构成对TDDFT或其他计算方法的严格测试。

Professor Stephen Drucker, Department of Chemistry at the University of Wisconsin - Eau Claire is funded by the Chemical Structure, Dynamics and Mechanisms A (CSDM-A) program for "Spectroscopic and Computational Studies of Alpha, Beta-Unsaturated Carbonyl Compounds in Triplet Excited States." Triplet states (species having two unpaired electrons) play a central role in many reactions that occur in the presence of light. Prof. Drucker and his group are investigating the nature of the triplet states of a series of organic molecules and aree exploring the differences between the triplet states and their singlet (the species that has no unpaired electrons) counterparts. These studies give fundamental insights into light induced chemical reactions. In addition, the experiments provide benchmark spectroscopic information for testing or refining computational treatments of chemical species. In this project, undergraduate group members will conduct in-depth research. Such opportunities add substantial value to the undergraduate education program, and can also foster rich opportunities for advanced study. Ongoing collaborations with investigators at Purdue will enable Prof. Drucker's undergraduates to participate in a range of activities. In turn, graduate students in the collaborating research group will be able to explore faculty careers at undergraduate institutions as they interact with Prof. Drucker and his students from UW-Eau Claire.The cavity ringdown (CRD) spectra of acrolein and isotopically substituted derivatives under the cooling conditions of a free-jet expansion, using a slit nozzle source are being recorded. These experiments afford high-precision inertial constants that will be used to determine a substitution structure for the T1 state. Experimental geometrical parameters will be compared with predictions of equilibrium geometry from high-level calculations. In a second component of the project, CRD at room temperature or in a planar free-jet expansion is used to characterize the lowest triplet states of monocyclic alpha,beta-unsaturated carbonyl compounds. Studies on cyclic enones, including cyclic lactones, provide information on the relative energies of the triplet (n,pi*) and (pi,pi*) states, the propensity for configuration mixing, and hyperconjugation between these molecules. The ability to reproduce such differences will constitute a stringent test of TDDFT or other computational methods.