RUI: Quantum Kinetic Studies of Molecule Formation and Destruction

Atomic and molecular collision processes are studied, with emphasis on the calculation of state-resolved rate coefficients for systems of current experimental and/or observational interest. A primary goal of this project is to provide theoretical data for systems and processes where reliable experimental data are either limited, or not currently available, thereby filling ?knowledge gaps? that sometimes hinder the modeling of astrophysical or other environments. This is particularly important for processes in which molecules are either formed, or destroyed, as these are important in many applications, including astrophysical models of photodissociation regions, protoplanetary disks of young stellar objects, collisions within ultracold gases, and in searches for better and less expensive catalytic materials for hydrogen storage. The project is designed to integrate research, teaching, and educational outreach and to provide an excellent opportunity for undergraduates to begin training for STEM careers. A novel approach for calculating formation and destruction rate constants will be employed which ensures detailed balance and self-consistency with the steady-state solution of an underlying master equation for any combination of kinetic and radiation temperature and gas density. This approach is expected to provide a substantial improvement over conventional kinetic models such as orbiting resonance theory, which are currently in wide use. Applied aspects which aim to push existing methodologies in quantum collision theory will be pursued. Dynamical de-coupling approximations will be studied and benchmarked against numerically exact results obtained from full-dimensional close-coupling calculations for collisions involving two diatomic molecules. Large databases of collisional and radiative rate coefficients will be developed in order to improve and extend the predictive capabilities for non-equilibrium systems. 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.