Dynamics of Ion-Radical Collisions: Imaging Studies

离子自由基碰撞动力学：成像研究

• 批准号: 1265406
• 负责人: James Farrar
• 金额: $ 41.94万
• 依托单位: University of Rochester
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2017-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1265406&HistoricalAwards=false
• 关键词: Dynamics; Ion; Radical; Collisions; Imaging

In this project supported by the Chemical Structure, Dynamics and Mechanisms Program of the Division of Chemistry, Professor James Farrar of the University of Rochester and his research group will explore the collisions of free radicals and atomic or molecular ions, employing the velocity map imaging (VMI) method for product detection, using the instrument developed during the initial grant period. By employing a pulsed supersonic source of free radicals such as CH3 and C3H5, and an electron impact or discharge source of low energy cations such as N2+, N+, C+, O2+, and O+, and anions such as H-, O-, O2-, and OH-, the VMI detection method will produce differential cross sections in kinetic energy and angle. Of particular interest are the bond formation reactions that yield C-C, C-O, C-N, N-O, and H-H bonds. For anionic reactions, free electrons produced by associative detachment will be detected. The experiments will produce information on the dynamics of reactions of low energy ions with free radicals, an area of ion chemistry with few extant examples in the literature. The work will address the serious deficiencies of models for electrical discharges and the chemistry of planetary atmospheres that do not include ion-radical reactions. A study of the H- + H associative detachment reaction will have important implications for astrophysics. In addition to characterizing the dynamics of these chemical systems, this research will provide a deeper understanding of reactivity patterns and a molecular understanding of the chemistry that takes place in reactive ion etching, and in atmospheric and extraterrestrial chemistry. The instrumental technique development may have impacts in various subdisciplines of chemistry, including mass spectrometry and ion imaging. The students and post-doctoral associates involved in this research will contribute to the national scientific and economic infrastructure through the development of new measurement technologies, new high value-added products, and the further training of scientific personnel.

在这个由化学系化学结构、动力学和机制项目支持的项目中，罗彻斯特大学的James Farrar教授和他的研究小组将使用最初资助期间开发的仪器，采用速度图成像（VMI）方法进行产品检测，探索自由基与原子或分子离子的碰撞。VMI检测方法采用CH3、C3H5等自由基的脉冲超音速源，以及N2+、N+、C+、O2+、O+等低能阳离子和H-、O-、O2-、OH-等阴离子的电子撞击或放电源，产生动能和角度的微分截面。特别有趣的是生成C-C、C-O、C-N、N-O和H-H键的成键反应。对于阴离子反应，将检测到由缔合分离产生的自由电子。实验将产生低能离子与自由基反应动力学的信息，这是离子化学的一个领域，在文献中很少有现存的例子。这项工作将解决不包括离子自由基反应的放电和行星大气化学模型的严重缺陷。H- + H缔合剥离反应的研究对天体物理学具有重要意义。除了描述这些化学系统的动力学特征外，这项研究还将提供对反应性模式的更深入理解，以及对反应性离子蚀刻、大气和地外化学中发生的化学的分子理解。仪器技术的发展可能会对化学的各个分支学科产生影响，包括质谱和离子成像。参与这项研究的学生和博士后将通过开发新的测量技术、新的高附加值产品和进一步培养科学人才，为国家的科学和经济基础设施做出贡献。