RUI: Exploring Differences between Condensed Phase Photolysis and Radiolysis

RUI：探索凝聚相光解和辐射分解之间的差异

• 批准号: 1465161
• 负责人: Christopher Arumainayagam
• 金额: $ 29万
• 依托单位: Wellesley College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-15 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1465161&HistoricalAwards=false
• 关键词: RUI; Exploring; Differences; between; Condensed

With with award, the Chemical Structure, Dynamics, and Mechanisms (CSDM-A) Program of the Division of Chemistry is funding Professor Christopher Arumainayagam at Wellesley College to study chemical reactions that are driven by interactions with light and/or electrons. Dr. Arumainayagam has devised probes to study the composition of nanoscale thin films under ultrahigh vacuum conditions before and after irradiation by low-energy electrons or photons. These probes enable his team to observe and characterize the subtle but important chemical changes induced by irradiation. This important category of chemical reactions impacts low-temperature plasmas used in industrially important processes such as plasma etching; use of low-energy electrons instead of photons for highly selective bond dissociations; identification of tracer molecules associated with specific pathways for interstellar synthesis of complex organic molecules (COM); and the relative roles of electrons and photons in atmospheric processes. Involvement of women and minority undergraduate students in this research is planned to promote diversification of the STEM workforce. The work specifically seeks to assess the differences and similarities between reactions initiated by low-energy ( 8 eV) electrons and photons. Target systems include condensed-phase ammonia, water and methanol, each of which is investigated using post-irradiation temperature programmed desorption, post-irradiation infrared reflection absorption spectroscopy, and isothermal electron/photon-stimulated desorption. Electrons/photons with sub-ionization energies are used to avoid production of low-energy secondary electrons, thereby ensuring that fundamental differences between electron and photon irradiation are probed. Among the objectives of the research are: (i) to measure the effective cross-section for electron/photon-induced reaction and desorption, and to identify all of the electron/photon-induced reaction products; (ii) to study the dependence of the reaction cross-sections and yields on electron/photon fluence, incident electron/photon energy, and film thickness; and (iii) to determine if the products identified by post-irradiation temperature-programmed desorption are nascent radiolysis products. The studies are designed to establish whether electron-induced condensed phase reactions generate unique molecular species; and whether electrons are more effective than photons for initiating specific condensed phase reactions.

随着奖励，化学划分的化学结构，动力学和机制（CSDM-A）计划是为韦尔斯利学院的Christopher Arumainayagam教授提供资金，以研究由与光和/或电子相互作用的化学反应。 Arumainayagam博士已经设计了探针，以研究低能量电子或光子照射之前和之后的超高真空条件下纳米级薄膜的组成。 这些探针使他的团队能够观察并表征辐射引起的微妙但重要的化学变化。 这种重要的化学反应类别影响了在工业重要过程中使用的低温等离子体，例如等离子体蚀刻。使用低能电子而不是光子进行高度选择性的键离解；鉴定与特定途径相关的示踪剂分子，用于星际合成的复杂有机分子（COM）；电子和光子在大气过程中的相对作用。 计划在这项研究中参与妇女和少数族裔本科生，以促进STEM劳动力的多样化。 这项工作专门旨在评估低能（8 eV）电子和光子引发的反应之间的差异和相似性。目标系统包括凝结相氨，水和甲醇，每种氨都可以使用后辐射温度程序编程的解吸，辐射后红外反射吸收光谱以及等温电子/光子刺激的呼吸进行研究。具有亚电离能的电子/光子用于避免产生低能二级电子，从而确保探测电子和光子照射之间的基本差异。研究的目标包括：（i）测量电子/光子诱导的反应和解吸的有效横截面，并鉴定所有电子/光子诱导的反应产物； （ii）研究反应横截面的依赖性以及对电子/光子通量，入射电子/光子能和膜厚度的依赖性； （iii）确定通过辐射后温度填充识别的产物是否是新生的辐射溶解产物。研究旨在确定电子诱导的冷凝相反应是否会产生独特的分子物种。以及电子是否比光子更有效，用于启动特定的凝结相反应。