Interaction of Low-energy Positrons with Atoms and Molecules

低能正电子与原子和分子的相互作用

• 批准号: 0755809
• 负责人: Clifford Surko
• 金额: $ 59万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0755809&HistoricalAwards=false
• 关键词: Interaction; Low; energy; Positrons; Atoms

This project focuses on experimental studies of the interaction of low-energy positrons with atoms and molecules using a high-resolution, trap-based positron beam and specially designed techniques to study scattering and annihilation processes. Recent theoretical and experimental results provide new topics for study, including understanding the nature of the orders-of-magnitude enhancements of positron annihilation on molecules that is mediated by vibrational Feshbach resonances. Key objectives of the research include understanding the nature of these resonances and the associated phenomena of positron binding to molecules and intramolecular vibrational energy redistribution. Other research topics include studies of resonance and threshold effects in positron scattering and studies of new targets including carbon-60 and metal atoms. In the broader view, the work seeks to establish aspects of a quantitative chemistry of matter and antimatter.The work can be expected to aid in enabling technological applications of low energy positrons, such as developing new methods to ionize large molecules and a new generation of positron beam sources for the characterization of materials. While focusing on research in atomic physics involving antimatter, this project also has impacts in other areas. It involves graduate student and post-doctoral researchers at all levels from the planning of experiments to the dissemination of research results. The project involves small-scale experiments that are an excellent training ground for scientific and technical personnel. The work is communicated broadly, not only to physics audiences but also to those involved in plasma, chemical, and materials science, and gaseous electronics research.

该项目的重点是使用高分辨率、基于陷阱的正电子束和专门设计的技术对低能正电子与原子和分子的相互作用进行实验研究，以研究散射和湮灭过程。最近的理论和实验结果提供了新的研究课题，包括了解的性质的数量级增强的正电子湮没分子介导的振动Feshbach共振。 研究的主要目标包括了解这些共振的性质以及正电子与分子结合和分子内振动能量重新分布的相关现象。 其他研究课题包括研究正电子散射中的共振和阈值效应，以及研究包括碳60和金属原子在内的新目标。从更广泛的角度来看，这项工作旨在建立物质和反物质的定量化学方面。这项工作有望有助于实现低能正电子的技术应用，例如开发新的方法来识别大分子和新一代的正电子束源来表征材料。虽然该项目侧重于涉及反物质的原子物理学研究，但它也对其他领域产生影响。 它涉及从实验规划到研究成果传播的各个层面的研究生和博士后研究人员。该项目涉及小规模实验，是科学和技术人员的一个极好的培训场所。 这项工作是广泛传播的，不仅对物理观众，而且对那些参与等离子体，化学，材料科学和气体电子学研究。