RUI: Condensed Phase Radiolysis vs. Photolysis

RUI：凝聚相辐射分解与光解

• 批准号: 1955215
• 负责人: Christopher Arumainayagam
• 金额: $ 38.49万
• 依托单位: Wellesley College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1955215&HistoricalAwards=false
• 关键词: RUI; Condensed; Phase; Radiolysis; vs.

With this award, the Chemical Structure, Dynamics, and Mechanisms A (CSDM-A) program of the Division of Chemistry is funding Professor Christopher Arumainayagam of Wellesley College to study the differences and similarities between condensed-phase (as opposed to gas-phase) chemical reactions driven by low-energy electrons and light (photons). The main goal is to provide detailed chemical explanations (at the level of the mechanisms of molecular interactions) for macroscopic effects such as how photon- and electron-induced ice chemistry contribute to the (1) ozone hole over the Antarctic and (2) formation of prebiotic (precursors to life) molecules such as glycine in outer space. As well as providing insight into the energetic processing of ices in nature, Professor Arumainayagam’s studies may help to better control industrial chemical reactions to form specific products without unwanted side products. For example, both photons and electrons play a critical role in extreme ultraviolet lithography (EUVL), which is a next-generation manufacturing technique of semiconductor chips critical for better smartphones. In addition to scientific broader impacts to knowledge of ice chemistry, atmospheric chemistry, astrobiology, and industrial chemistry, this Research at Undergraduate Institutions award has a significant impact on education of female undergraduate students, including promoting participation by minority and economically disadvantaged students, and the award includes plans to further promote diversity within the STEM workforce. Students participating in research under this award gain experience with advanced experimental techniques, in addition to skills such as critical thinking, troubleshooting, and problem solving in the research lab.Radiolysis and photolysis of condensed phase NH3, H2O, and CH3OH are being investigated under ultrahigh vacuum (UHV) conditions by using post-irradiation temperature-programmed desorption (TPD), post-irradiation infrared spectroscopy, and isothermal electron/photon-stimulated desorption (ESD/PSD) techniques. Electrons/photons with sub-ionization energies (10 eV) are employed to avoid the production of cations and low-energy secondary electrons, ensuring that fundamental differences between electrons and photons can be probed. The experiments involve a recently-commercialized high-intensity laser-driven low-energy (7.4 eV) broadband photon source. When coupled to a monochromator, purchased with funds from this award, this high-intensity photon source will allow for wavelength-dependent condensed phase photochemistry studies that have previously been done at synchrotron facilities. Studying condensed-phase radiolysis and photolysis in a single UHV chamber using the same experimental protocol is critical in exploring fundamental differences between the dynamics of condensed phase electron- and photon-induced reactions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

有了这个奖项，化学系的化学结构，动力学和机制A（CSDM-A）计划资助韦尔斯利学院的Christopher Arumainayagam教授研究由低能电子和光（光子）驱动的凝聚相（与气相相反）化学反应之间的差异和相似之处。 主要目标是为宏观效应提供详细的化学解释（在分子相互作用机制的层面上），例如光子和电子诱导的冰化学如何促成（1）南极上空的臭氧洞和（2）在外层空间形成益生元（生命的前体）分子，如甘氨酸。 除了深入了解自然界中冰的高能加工过程外，Arumainayagam教授的研究还有助于更好地控制工业化学反应，以形成特定的产品，而不会产生不必要的副产品。 例如，光子和电子在极紫外光刻（EUVL）中发挥着关键作用，EUVL是下一代半导体芯片制造技术，对更好的智能手机至关重要。 除了对冰化学、大气化学、天体生物学和工业化学知识产生更广泛的科学影响外，该本科院校研究奖对女本科生的教育产生了重大影响，包括促进少数民族和经济困难学生的参与，该奖项还包括进一步促进STEM劳动力多样性的计划。 参加该奖项研究的学生获得了先进的实验技术经验，以及批判性思维，故障排除和解决问题的能力。在超高真空（UHV）条件下，通过使用辐照后程序升温脱附（TPD），辐照后红外光谱，和等温电子/光子刺激解吸（ESD/PSD）技术。 使用具有亚电离能（10 eV）的电子/光子来避免产生阳离子和低能二次电子，确保可以探测电子和光子之间的根本差异。 实验涉及最近商业化的高强度激光驱动的低能量（7.4 eV）的宽带光子源。 当耦合到一个单色器，从这个奖项的资金购买，这种高强度的光子源将允许波长依赖的凝聚相光化学研究，以前已经在同步加速器设施。 使用相同的实验方案在单个超高真空室中研究凝聚相辐解和光解对于探索凝聚相电子和光子诱导反应动力学之间的根本差异至关重要。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估而被认为值得支持。

项目成果

A New Method for Simulating Photoprocesses in Astrochemical Models

天体化学模型中模拟光过程的新方法

• DOI: 10.3847/1538-4357/abd778
• 发表时间: 2021
• 期刊: The Astrophysical Journal
• 作者: Mullikin, Ella;Anderson, Hannah;O’Hern, Natalie;Farrah, Megan;Arumainayagam, Christopher R.;van Dishoeck, Ewine F.;Gerakines, Perry A.;Vasyunin, Anton I.;Majumdar, Liton;Caselli, Paola
• 通讯作者: Caselli, Paola