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The Gas-Phase Chemical Dynamics (GPCD) group uses complementary theoretical and experimental methods to explore and determine the thermochemistry, dynamics, and kinetics of gas-phase chemical processes.

Our goal is to develop a fundamental understanding of gas-phase chemistry, with an emphasis on elementary chemical reactions, non-reactive energy transfer processes, and coupled kinetics processes. This understanding will ultimately provide the foundation for the predictive modeling of gas-phase chemistry in a wide range of disciplines, including combustion, atmospheric chemistry, low-temperature plasmas, aerosols, and controlled gas-phase particle synthesis. Furthermore, feedback from improved modeling into experiments and theory can reveal fundamental deficiencies in the models, which will ultimately provide a stronger foundation for our understanding.

Our approach combines a theoretical effort in the energetics, dynamics, and kinetics of chemical reactions with an experimental effort in thermochemistry, dynamics, and kinetics under both chemically isolated conditions and more complex conditions. The group’s members maintain expertise balanced among theory, experiment, and modeling.

The theoretical effort involves both the development of new theoretical methods and the application of existing methods to outstanding problems in gas phase chemical dynamics. Electronic structure techniques that determine intermolecular forces, dynamics techniques that determine molecular responses to these forces, and kinetics techniques to determine the rates of the resulting reactions are all being pursued. Modeling of more complex chemistry including both coupled kinetics and transport is also being developed, along with new approaches for global uncertainty and sensitivity analyses. The group has a growing effort to fully automate this modeling though high-performance computing.

The experimental effort includes flow tube studies across a broad temperature range, thermal reaction kinetics measurements in shock tubes at high temperatures, state- and angle-resolved photoionization and photodissociation measurements, and chirped-pulse millimeter-wave studies of molecules in reactive environments. Reaction rates, branching ratios, product distributions, and ion-cycles for thermochemical determinations are all being examined. Increasingly, the group is developing more systematic approaches to problem selection, for example, through sensitivity analysis of chemical kinetic models, and through network-based analysis of thermochemical data. The group’s greatest assets are the strong interactions between group members and the synergy that results from the combination of theoretical and experimental efforts.