Enabling Fundamental Charge Transfer Measurements for Molecular Ions with Atomic H

该项目的重点是利用位于田纳西州橡树岭的橡树岭国家实验室的合束装置测量H/D原子与H2+(以及同位素系统HD+和D2+)之间电荷转移的绝对截面，该装置在用于原子离子测量多年后，最近被用于分子离子研究。这些测量的靶截面范围是mev/u到kev/u，这是一个很难从实验和理论上研究的区域。重点将更多地放在低碰撞能量上，那里的碰撞时间足够长，足以采样振动模，并允许通过核替代进行电荷转移。这些结果将对我们理解碰撞动力学产生重要影响，并将为基础物理、等离子体(实验室和天体物理)物理、生物物理等各个学科提供重要信息。例如，对于聚变托卡马克冷偏滤器区域中发现的高密度-低温等离子体的建模，至今文献中仍然缺失的整个光谱是必要的。这项工作所支持的基础研究将为基础物理学的实验进步做出重大贡献。它将引起来自不同领域的理论家的兴趣。除了科学意义之外，来自太平洋联合学院的本科生的密切参与将具有重要的价值。太平洋联合学院是一所以本科为主的机构，皮耶希是该学院的教员。该项目有丰富的教育内容，并将扩大PI与橡树岭国家实验室物理部的合作。这些实验涉及不同层次的实验物理问题。有些，比如在当前的数据采集软件中加入更复杂的统计分析，将是非常令人兴奋的本科生水平的任务。这些学生将在橡树岭国家实验室参加最先进的测量；否则他们将没有其他机会直接了解物理研究。此外，由于太平洋联合学院在种族多样性方面一直排名第一，不包括国际学生，在学士学位学院地区，该项目可能会对代表不足的少数族裔产生影响。

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.