RUI: Collaborative Research: Experimental and Theoretical/Computational Studies of Low Energy Electron Collisions with Molecules

RUI：合作研究：低能电子与分子碰撞的实验和理论/计算研究

• 批准号: 0968874
• 负责人: Murtadha Khakoo
• 金额: $ 6.65万
• 依托单位: CSU Fullerton Auxiliary Services Corporation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-10-01 至 2014-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0968874&HistoricalAwards=false
• 关键词: RUI; Collaborative; Research; Experimental; Theoretical

This work continues and further develops a highly successful collaboration among several institutions in the US and Brazil to investigate the interactions of low-energy electrons with polyatomic molecules, and in particular with biofuels and other biological molecules. The collaboration includes scientists from California State University, Fullerton, the California Institute of Technology, the State University of Campinas. It involves both experimental and theoretical groups who have come together to work jointly on problems where they have overlapping interests and complementary expertise. Major focuses in future work will be electron-impact excitation of polyatomic molecules and dissociative electron attachment to polyatomics. Calculations and measurements of electron-impact excitation processes in polyatomics are challenging, and results are scarce despite the need for such data in understanding reactive plasmas and discharges. To build expertise in this area, measurements and calculations are carried out for two prototypical molecules, ethylene and furan, both of which have low-lying triplet states well isolated from other thresholds. Following that, measurements and calculations of electron-impact excitation cross sections for methanol and ethanol will be done. Electron-impact excitation of these prototypical and ubiquitous alcohols is of fundamental interest and also has high technological relevance: dissociative excitation and ionization are key processes in spark ignition of alcohol fuels, and rate data are needed for modeling and optimizing the ignition process. Collaborators in Brazil affiliated with the Bioethanol Science and Technology Center in Campinas are initiating studies of spark ignition that will involve both laboratory measurements and numerical modeling, and those studies will make direct use of the electron-impact excitation cross sections that will be measured and calculated as part of this project.The broader impacts are that electron-molecule collisions at low energy present many features of fundamental interest and pose a great challenge to both experimental and computational methods, but they also have wide technological significance, being relevant to the physics of plasmas and discharges, the upper atmosphere, and circumstellar and interstellar media. In the specific case of methanol and ethanol, accurate cross-section data for the major collision processes, including elastic scattering, excitation, and ionization, are needed for numerical modeling and optimization of discharges used to ignite alcohols used as fuels. Such modeling may lead to improved spark-plug designs that produce more complete combustion and thus higher fuel efficiency. Moreover, an understanding of electron driven excitation and dissociation in the alcohols may give insights into the same processes in related biomolecules, including sugars. A central component of the project is providing opportunities for young scientists to gain experience doing science in an international context, with US students making extended visits to do research in Brazil and vice versa. This project is co-funded with the Americas Program of the Office of International Science and Engineering.

这项工作仍在继续，并进一步发展了美国和巴西多个机构之间非常成功的合作，以研究低能电子与多原子分子，特别是与生物燃料和其他生物分子的相互作用。此次合作包括来自加州州立大学富勒顿分校、加州理工学院和坎皮纳斯州立大学的科学家。它涉及实验和理论小组，他们聚集在一起共同解决具有重叠兴趣和互补专业知识的问题。未来工作的主要重点将是多原子分子的电子碰撞激发和多原子的离解电子附着。多原子中电子碰撞激发过程的计算和测量具有挑战性，尽管需要此类数据来理解反应等离子体和放电，但结果却很少。为了建立该领域的专业知识，对乙烯和呋喃这两种典型分子进行了测量和计算，这两种分子都具有与其他阈值良好隔离的低位三重态。接下来，将对甲醇和乙醇的电子轰击激发截面进行测量和计算。这些典型且普遍存在的醇的电子碰撞激发具有根本意义，并且具有很高的技术相关性：解离激发和电离是醇燃料火花点火的关键过程，并且需要速率数据来建模和优化点火过程。隶属于坎皮纳斯生物乙醇科学技术中心的巴西合作者正在启动火花点火研究，该研究将涉及实验室测量和数值模拟，这些研究将直接利用电子碰撞激发截面，作为该项目的一部分进行测量和计算。更广泛的影响是，低能量下的电子-分子碰撞呈现出许多令人感兴趣的基本特征，并对 实验和计算方法，但它们也具有广泛的技术意义，与等离子体和放电、高层大气以及星际和星际介质的物理相关。在甲醇和乙醇的具体情况下，需要主要碰撞过程（包括弹性散射、激发和电离）的准确横截面数据，以对用于点燃用作燃料的醇的放电进行数值建模和优化。这种建模可以改进火花塞设计，从而产生更完全的燃烧，从而提高燃料效率。此外，对醇中电子驱动的激发和解离的理解可以深入了解相关生物分子（包括糖）中的相同过程。该项目的核心组成部分是为年轻科学家提供在国际背景下获得科学经验的机会，美国学生可以长期访问巴西进行研究，反之亦然。该项目是与国际科学与工程办公室美洲项目共同资助的。