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.

这个项目主要是利用高分辨率的陷阱正电子束和专门设计的技术来研究散射和湮灭过程，以实验研究低能正电子与原子和分子的相互作用。最近的理论和实验结果为研究提供了新的课题，包括理解正电子湮没对分子的数量级增强的本质，这种增强是由振动Feshbach共振介导的。这项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配的相关现象。其他研究课题包括正电子散射中的共振和阈值效应的研究，以及包括碳-60和金属原子在内的新目标的研究。从更广泛的角度来看，这项工作旨在建立物质和反物质的量化化学。这项工作有望帮助实现低能正电子的技术应用，例如开发新的方法来电离大分子，以及用于表征材料的新一代正电子束源。在专注于反物质原子物理研究的同时，该项目也在其他领域产生了影响。它涉及从实验计划到研究成果传播的所有级别的研究生和博士后研究人员。该项目涉及小规模实验，是科技人员的极好培训基地。这项工作被广泛传播，不仅面向物理学观众，也面向从事等离子体、化学、材料科学和气体电子学研究的人。