barker
734-763-6239
Methodologies: Physics-Specific Methods

John Barker

Professor Emeritus, Climate and Space Sciences and Engineering

We publish computer codes for computational chemical reaction kinetics calculations. Our long-term aim (not yet achieved!) is to develop predictive tools that are as good as experiments. Toward that end, we use statistical rate theories to predict thermal rate constants for comparison with experimental data and for making predictions. An example is Miller’s very powerful Semi-Classical Transition State Theory, which we implemented by using a variant of the Wang-Landau algorithm. We also use our codes, which are based on Gillespie’s stochastic simulation algorithm, for solving the chemical/collisional master equation for complicated unimolecular reaction systems. These calculations are used for interpreting experiments, interpolating and extrapolating sparse experimental data, and for predicting chemical product yields and rates of reactions. Our work is mostly applied to non-equilibrium atmospheric and combustion chemistry.
Chemical reaction system for nitrate radical (NO3) reacting with ethylene (C2H4). The figure shows several reaction pathways and the energies of the intermediates as the reaction progresses from the reactants (upper left) to the final products (on the right). Oxygen atoms red, nitrogen atoms are blue, carbon atoms are darker gray, and hydrogen atoms are lighter gray. [Nguyen, T. L., J. Park, K. Lee, K. Song, and J. R. Barker (2011), Mechanism and Kinetics of the Reaction NO3 + C2H4, J. Phys. Chem. A, 115, 4894–4901.]

Chemical reaction system for nitrate radical (NO3) reacting with ethylene (C2H4). The figure shows several reaction pathways and the energies of the intermediates as the reaction progresses from the reactants (upper left) to the final products (on the right). Oxygen atoms red, nitrogen atoms are blue, carbon atoms are darker gray, and hydrogen atoms are lighter gray. [Nguyen, T. L., J. Park, K. Lee, K. Song, and J. R. Barker (2011), Mechanism and Kinetics of the Reaction NO3 + C2H4, J. Phys. Chem. A, 115, 4894–4901.]