In this project, funded by the Experimental Physical Chemistry Program of the Chemistry Division, Prof. Stephen Drucker and his undergraduate students at the University of Wisconsin-Eau Claire will continue their spectroscopic studies of small organic molecules in triplet excited states. Triplet states (species having two unpaired electrons) play a central role in many photochemical reactions. Prof. Drucker and his group have been investigating the lowest triplet states of a series of cyclic conjugated enone molecules. They have explored structural and dynamical differences between the triplet states and their singlet counterparts. Beyond the fundamental insights offered by such investigation, the experiments provide benchmark spectroscopic information for testing or refining computational treatments of excited states and the photochemical processes they mediate. In the proposed research, students will use sensitive spectroscopic techniques - cavity ringdown absorption and phosphorescence excitation - to determine frequencies of the C=O and C=C stretching vibrations in the triplet states. The data will complement information that the group obtained previously on low-frequency ring vibrations of the cyclic enones. The researchers will also extend their work to include lactone and anhydride molecules analogous to the enones. Heretofore, the information available from the room temperature spectra has been limited by spectral congestion due to hot bands. To eliminate the hot bands, Prof. Drucker's group proposes to record the cavity ringdown spectra under jet-cooled conditions using a slit nozzle source.
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, Texas A&M, and USC) will enable Prof. Drucker's undergraduates to participate in a range of activities. In turn, graduate students in the collaborating research groups will be able to explore faculty careers at undergraduate institutions as they interact with Prof. Drucker and his students from UW-Eau Claire.
