In this project funded by the Chemical Structure, Dynamics, and Mechanism-B Program of the Chemistry Division, Professor Robert J. McMahon of the Department of Chemistry at the University of Wisconsin-Madison investigates the behavior of organic compounds under extreme conditions of temperature, pressure, or radiation. These conditions, which are similar to the conditions found in flames (combustion) or in space, cause the degradation of organic compounds and generate a complex mixture of highly reactive products. This project explores the properties and chemical reactions of these reactive molecules. This research provides a foundation for understanding two very different problems ? one involving combustion and another involving the chemistry of space. Combustion of organic fuels is central to our nation?s energy supply and national economy. A fundamental understanding of combustion offers the possibility of enhancing the energy efficiency of fuel combustion and minimizing pollutants (soot) that arise from incomplete combustion. In interstellar space, it is now known that hundreds of different organic compounds exist throughout the galaxy in environments that are harsh because they are so hot (near stars) or because they are so cold (far from stars). Studying these environments is a crucial step in understanding the distribution of organic material in the universe and identifying molecules that could be precursors to life. This research program supports the education of graduate and undergraduate students in the study of complex chemical problems as part of an interdisciplinary research team. Training in mechanistic organic chemistry provides a valuable foundation for subsequent careers in industry or academia. Professor McMahon and his student engage in a variety of science education and outreach activities.
This proposal addresses challenges in mechanistic organic chemistry that are relevant to our understanding of harsh reaction environments. The current proposal develops these issues along three major lines: 1) generation, detection, and characterization of key chemical targets by rotational spectroscopy, 2) spectroscopy and photochemistry of carbon-chain molecules, and 3) quantum mechanical tunneling in organic chemistry. The scientific impact of the proposed research reaches beyond chemistry and cuts across diverse areas of contemporary science. Studies of spin delocalization and spin polarization underpin the development of new organic materials with novel electrical and magnetic properties. Studies of reactive organic species contribute to a fundamental understanding of combustion. The Atacama Large Millimeter Array (ALMA), an NSF-funded astronomical interferometer of radio telescopes in northern Chile, is generating a deluge of new radio-astronomical data. These data can be interpreted only by comparison with laboratory spectra of the type that are obtained in this project.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
