Temporary Anions and Dissociative Attachment: Probes of Intra- and Intermolecular Interactions

临时阴离子和解离附着：分子内和分子间相互作用的探针

• 批准号: 9710076
• 负责人: Paul Burrow
• 金额: $ 34.29万
• 依托单位: University of Nebraska-Lincoln
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-01 至 2000-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9710076&HistoricalAwards=false
• 关键词: Temporary; Anions; Dissociative; Attachment; Probes

In this project in the Experimental Physical Chemistry Program of the Chemistry Division, Burrow (University of Nebraska) and Jordan (University of Pittsburgh) will continue joint experimental and theoretical studies of temporary anion formation in gas-phase substituted hydrocarbons. Experimental studies at both institutions will examine vibrational excitation and dissociative attachment (DA) reactions in which stable fragment anions are produced. Both total DA cross sections and vertical attachment energies (VAEs) for formation of temporary anions will be measured. A new instrument will be constructed to measure the angular dependence of fragment anions produced by DA. The effect of solvation on the energies and decay properties of temporary anions will be examined in methyl chloride (CH3Cl) co-expanded with solvents such as water. High-level electronic structure calculations will be carried out to predict how the vertical attachment energy is influenced by the solvation. A powerful means of visualizing molecular structure and chemical reactivity is provided by the concept of occupied and unoccupied electronic states, which are also known as orbitals. Photoelectron spectroscopy has long provided a means of studying occupied orbitals, but until recently the corresponding data for normally unoccupied orbitals has been scarce. This work aims at gathering such data, thereby helping to answer key chemical questions on structure and bonding in complex molecules. It also offers data crucial to models of electron transfer, which is the mechanism involved in a large variety of chemical processes, such as photosynthesis, light-induced desorption from surfaces, chemical carcinogenesis, and bioremediation.

在化学系实验物理化学项目的这个项目中，Burrow（内布拉斯加大学）和Jordan（匹兹堡大学）将继续对气相取代烃中临时阴离子形成的联合实验和理论研究。 两个机构的实验研究将检验振动激发和产生稳定片段阴离子的解离附着（DA）反应。 将测量总 DA 横截面和形成临时阴离子的垂直附着能 (VAE)。 将建造一个新仪器来测量 DA 产生的碎片阴离子的角度依赖性。 将在与水等溶剂共膨胀的氯甲烷 (CH3Cl) 中检查溶剂化对临时阴离子的能量和衰变特性的影响。 将进行高级电子结构计算，以预测垂直附着能如何受到溶剂化的影响。 占据和未占据电子态（也称为轨道）的概念提供了可视化分子结构和化学反应性的强大手段。 光电子能谱长期以来提供了研究占据轨道的一种手段，但直到最近，通常未占据轨道的相应数据还很少。 这项工作旨在收集此类数据，从而帮助回答有关复杂分子结构和键合的关键化学问题。 它还提供对电子转移模型至关重要的数据，电子转移是涉及多种化学过程的机制，例如光合作用、光诱导表面解吸、化学致癌和生物修复。