17 - Energy Transfer Dynamics of Methane with Highly Vibrationally Excited Molecules
U Maryland, College Park
Chemistry and Biochemistry
Molecular collisions have a major effect on chemical reactions by adding or removing energy from the reactive coordinate. As a result, molecules can gain enough energy to cross the energy barrier and form products or, in contrast, they can be rendered nonreactive. These inelastic collisions between molecules will have an important impact on the overall combustion processes at higher pressure of the new generation of internal combustion engines. A quantum state-resolved study of how methane, the simplest hydrocarbon, exchanges energy with highly vibrationally excited molecules through collisions provides insight into how this energy is redistributed in these high pressure and temperature environments. High-resolution transient IR absorption spectroscopy was used to measure the rotational, translational, and vibrational energy gains of methane molecules after single collisions with vibrationally excited pyrazine molecules (Evib = 108 kcal mol-1). The product distributions show that rotational energy gain in the CH4 molecules is the dominant energy flow pathway. Small amounts of translational energy are observed and are related to the structure of methane.