Studies of Olefin Triplets and Triplet Biradicals

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This project will probe both the thermodynamic and kinetic factors involved in the formation and decay of alkene triplet states and triplet biradicals. By combining conventional photochemical techniques such as product analysis and quantum yield measurements with laser flash and time resolved photoacoustic calorimetry, a complete decription of triplet state photochemical processes will emerge. By combining the experimental results with theoretical calculations, a thorough and fundamental analysis of intersystem crossing and the corresponding energy surfaces involved will be developed. An important outcome of the investigation will be a better understanding of biradicals, and new methods for their production will be suggested. The investigation will provide critical and definitive conformation of theories for intersystem crossing from triplet to ground state surfaces and the factors, such as spin-orbit coupling, which control these processes. %%% This grant from the Organic Dynamics Program supports the continuing work of Professsor Richard A. Caldwell at The University of Texas at Dallas. These studies will probe the basic nature of the intermediate states which occur in chemical processes. By measuring the way that these intermediate species absorb light and how much heat is involved in their formation and decay, it is possible to predict how other similar, and in some cases not so similar, processes will proceed. Such fundamental knowledge, which is obtained by using specially designed instruments which are able to record phenomena which occur on the order of billionths of a second, will be combined with the theoretical predictions from computer calculations to provide a complete description of the energy requirements for converting one molecule into another via the use of light energy. The information gained will be useful in a variety of applications which use light to induce rapid and efficient changes, such as those which occur during the processing of computer chips.