The spectroscopy and photochemistry of key reactive intermediates: carbenes and carbocations

Marquette University, Milwaukee WI

Investigators

Abstract

Scott Reid of Marquette University is supported by the Experimental Physical Chemistry Program to carry out experiments that aim to answer key questions concerning the electronic structure and photochemistry of carbenes and carbocations. These species are important reactive intermediates, implicated in many organic and organometallic reactions, in combustion and the thermal decomposition of small organic molecules, and in stratospheric and interstellar chemistry. First, plans are to apply high resolution, state-selected double resonance techniques to obtain detailed information on the triplet state structure, spin-orbit mixing, and singlet-triplet gaps in a number of significant carbene species. A second phase will involve the examination of photophysics and photochemistry of simple halocarbenes. Preliminary studies have shown that these molecules can exhibit unusual photochemistry, which at present is not well understood. These studies will seek to characterize specific halocarbene photochemistry and provide new information on higher excited states that will serve as benchmarks for ab initio theory. A third phase will examine carbocations, which have long resisted gas-phase structural analysis despite their chemical importance. Following the Reid group''s recent observation of the first gas-phase electronic spectrum of a halocarbocation, the spectroscopy and dynamics of a series of halocarbocations will be studied using sensitive, high-resolution spectroscopic techniques. Outcomes from this research are expected to advance knowledge in areas of chemistry and environmental science, and serve as benchmarks for theoretical chemistry calculations. The projects will provide training for graduate and undergraduate students in a variety of important skill areas. Group members will play an active role in disseminating research results via journal publications and presentations at conferences.