This project focuses on measuring the absolute cross section of the charge transfer between H/D atom and H2+ (and the isotopic systems HD+ and D2+) with the merged-beams apparatus at Oak Ridge National Laboratory, in Oak Ridge, Tennessee, which has been recently made available for molecular ion investigations after being used for atomic ion measurements for years. The target cross section range for these measurements is meV/u to keV/u, which is known to be a very difficult region to investigate both experimentally and theoretically. The emphasis will be more on low collision energies where the collision time is long enough to sample rovibrational modes and to allow charge transfer via nuclear substitution. The results will have important impacts on our understanding of the collision dynamics and will provide important information for various disciplines such as fundamental physics, plasma (laboratory and astrophysical) physics, biophysics, etc. For instance, the entire spectrum which is still missing in the literature to this day is necessary for the modeling of high density-low temperature plasmas as found in cold divertor regions of a fusion tokamak. Also, the measurement will be used to benchmark theory.
The basic research supported by this work will contribute a significant incremental experimental progress in fundamental physics. It will generate interest on the part of theorists from different areas. Beyond its scientific implications, the close involvement of undergraduate students from Pacific Union College, a primarily undergraduate institution where PI is a faculty member at, will be of significant value. The project has a rich educational component and would extend a collaboration of PI with the Physics division of Oak Ridge National Laboratory. The experiments address experimental physics problems of different levels. Some, such as incorporating more sophisticated statistical analysis in the current data acquisition software, will be very exciting undergraduate level tasks. These students will take part in a state-of-the-art measurement at Oak Ridge National Laboratory; otherwise they would have no other opportunity to directly learn firsthand about physics research. Also, as Pacific Union College consistently ranked in the first places for racial diversity, not including international students, in baccalaureate colleges region, the project will potentially have impacts on the underrepresented minorities.
