For over a decade, my research group has investigated a wide range of problems in quantum collision theory. For many years we focused primarily on low-energy scattering of electrons and positrons by molecules, exploring such diverse topics as non-local, many-body interactions such as exchange and correlation, new collision theories for near-threshold excitations, model potentials for calculations on large, complex systems, and the determination of accurate cross sections required for applications such as laser kinetic modeling, plasma diagnostics, nanotechnology, and astrophysics. More recently, we have diversified this program, undertaking new research in such topics as multi-step laser excitation of atoms, orientation and alignment effects in electron-atom scattering, collisions of Rydberg atoms with rare-gas atoms, the physics of ultracold molecules, predissocation in molecular dimers, and electron transport in quantum devices. Pursuit of these questions involves formal mathematics and quantum mechanics, numerical algorithms and their computational implementation, and analysis of experimental data.

Our current research includes theoretical studies of dissociative attachment, the extension of density functional and many-body theories to bound-free correlation effects in continuum states in electron scattering, investigations of collision dynamics and other physical effects that participate in ultra-old molecular experiments now underway in our Department, studies of time-dependent wave packet scattering, inquiries into the fundamental nature of transport theory of electrons in molecules (a project aimed at resolving a long-standing, severe discrepancy between theory and experiment on a very basic electron-molecule collision problem), determination of accurate electron-molecule integral cross sections from measured angular distributions, the importance of bound-bound and bound-free correlation in electron scattering, and the application of R-matrix theory to problems in device physics. Many of these projects are collaborations with OU faculty and students.

An important feature of our research program is our vigorous, continuing collaboration with experimental and theoretical physicists at OU and at a variety of other institutions, including the Australian National University, the Joint Institute for Laboratory Astrophysics, IBM Research Laboratories, and the Los Alamos National Laboratory. These projects often entail visits of members of our group to other institutions and vice versa.