Negative Ion Photoelectron Spectroscopy of Atomic, Molecular and Cluster Anions

原子、分子和团簇阴离子的负离子光电子能谱

• 批准号: 2054308
• 负责人: Kit Bowen
• 金额: $ 60万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2054308&HistoricalAwards=false
• 关键词: Negative; Ion; Photoelectron; Spectroscopy; Atomic

With support from the Chemical Structure, Dynamics, and Mechanisms A (CSDM-A) Program in the Division of Chemistry, Professor Kit Bowen and his group at Johns Hopkins University are studying the negative ions that form when an extra electron is attached to an atom, molecule, or cluster. The addition of electrons to chemical systems can make the unexpected occur, enticing seemingly impossible processes to take place. For example, electrons drive, direct, induce, and initiate an astonishing variety of transformations, including DNA damage, proton transfer, molecular activation, and a vast array of electrochemical reactions. The negative ions that result from electron attachment are also crucial actors in chemical reaction mechanisms, playing key roles in organic chemistry, electrochemistry, and radiation biology. Electron-influenced processes in complex environments are ubiquitous. For these reasons, a microscopic understanding of basic phenomena involving excess electrons is essential. To probe these phenomena, Dr. Bowen and his group use a technique called negative ion photoelectron spectroscopy to measure how tightly electrons are bound to negatively charged atoms, molecules, and clusters. The experiments reveal detailed information about both the ions and their neutral counterparts, while also providing important benchmarks for computational chemistry. Considering the wide-ranging importance of electron-driven processes, the work in Dr. Bowen’s lab has interdisciplinary appeal, with impact ranging across fields as diverse as atmospheric chemistry, catalysis, radiation chemistry and biology, astrochemistry, and mass spectrometry. Dr. Bowen’s work also makes strong contributions to education and human resource development by mentoring graduate students who will become the scientists of tomorrow, by providing undergraduates from Johns Hopkins and other colleges and universities an opportunity to participate in cutting-edge research, and by giving high school, middle school, and elementary school students a glimpse into scientific research. The outreach efforts encourage participation from groups that are underrepresented in science.Dr. Bowen’s research examines electron-induced proton transfer (EIPT) reactions, weakly-bound (diffuse) excess electron states of atoms and molecules, and the properties of transient molecular anions. For example, the research team is exploring the role of EIPT in cluster anions, where they expect the internal interactions to be governed by the excess electron. EIPT is a wide-spread, perhaps even ubiquitous electron-assisted process. The team is also examining the relationship between EIPT in ground-state molecular anions and the process of excited-state intra-molecular proton transfer (ESIPT) in neutral molecules. Dr. Bowen’s research on weakly-bound (diffuse) excess electron states examines some of the most subtle interactions in chemistry; those between electrons and atoms or molecules. In this area, the research team is studying the formation and characterization of polarizability-bound electrons in xenon atomic cluster anions and in ground state anions of buckminsterfullerene; quadrupole-bound electrons in electronically metastable atomic metal anions; and multiple Rydberg electrons in metal-ammonia cluster anions. Although the electrons are weakly bound in each of these cases, they represent steps on a staircase of progressively stronger interactions. Finally, the research team is studying transient molecular anions using a unique approach, developed by Dr. Bowen, that combines Rydberg electron transfer with anion photoelectron spectroscopy (RET-aPES). The research team uses the RET-aPES technique to form and characterize valence anions of nucleobase molecules, the Criegee intermediate, and the hydrogen iodide molecule. They are also using RET-aPES to explore the barely studied, yet fundamentally important process of Penning electron detachment. These studies foster a deeper understanding of the earliest stages of electron damage to DNA, the electrophilic properties of important atmospheric intermediates, the unexpected stability of HI anion, and collisional anion destruction processes in energetic gaseous environments, such as flames and solar atmospheres. The outcomes from this broad research project are expected to have widespread impact across many fields of science. Additionally, the project provides advanced training opportunities for graduate and undergraduate research students, while also engaging K-12 students through Dr. Bowen's outreach activities.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.

在化学结构，动力学和机制A（CSDM-A）计划的支持下，Kit Bowen教授及其在Johns Hopkins University的小组正在研究当将额外的电子附在原子，分子或集群上时形成的负离子。将电子设备添加到化学系统中会导致出乎意料的发生，从而诱使发生似乎不可能发生的过程。例如，电子驱动，直接，诱导和引发了令人惊讶的变化，包括DNA损伤，质子转移，分子激活以及大量的电化学反应。电子附着引起的负离子也是化学反应机制中的关键参与者，在有机化学，电化学和辐射生物学中起关键作用。复杂环境中受电子影响的过程无处不在。由于这些原因，对涉及过量电子的基本现象的微观理解至关重要。为了探究这些现象，Bowen博士和他的小组使用一种称为负离子光电光谱的技术来测量电子与带负电荷的原子，分子和簇结合的紧密结合。这些实验揭示了有关离子及其中性对应物的详细信息，同时还为计算化学提供了重要的基准。考虑到电子驱动过程的广泛重要性，鲍恩博士实验室的工作具有跨学科的外观，其影响范围在大气化学，催化，放射化学和生物学，天文学和质谱等领域的范围内。鲍恩（Bowen）博士的工作还通过为明天的科学家而为教育和人力资源开发做出了巨大贡献，通过为约翰·霍普金斯（Johns Hopkins）和其他学院和大学的本科生提供参与尖端研究的机会，并让高中，中学和小学生一瞥科学研究，这是一个机会。推广工作鼓励参与科学中代表性不足的团体。鲍恩的研究考试具有电子诱导的质子转移（EIPT）反应，弱结合（扩散）超过原子和分子的电子状态，以及瞬时分子阴离子的特性。例如，研究团队正在探索EIPT在集群阴离子中的作用，他们期望内部相互作用由多余的电子支配。 EIPT是一个广泛的，甚至可能无处不在的电子辅助过程。该团队还在研究地下分子阴离子中的EIPT与中性分子中激发态内分子内质子转移（ESIPT）的过程之间的关系。鲍恩（Bowen）博士对弱结合的研究（扩散）超过电子状态，研究了化学中一些最微妙的相互作用。电子和原子或分子之间的那些。在这一领域，研究小组正在研究Xenon原子簇阴离子和Buckminsterfullerene的基态阴离子中极化性结合的电子产品的形成和表征。电子亚稳定原子金属阴离子中的四极杆结合的电子设备；以及金属 - ammonia簇阴离子中的多个rydberg电子。尽管这些情况在每种情况下都是弱结合的，但它们代表了逐步相互作用的楼梯上的步骤。最后，研究团队正在使用由Bowen博士开发的独特方法研究瞬时分子阴离子，该方法将Rydberg Electron转移与阴离子光电光谱（RET-APES）相结合。研究小组使用RET-ABE技术形成和表征核碱分子，Criegee中间体和碘化氢分子的价值阴离子。他们还使用ret-papes来探索几乎没有研究的培养电子脱离过程。这些研究促进了对电子损伤对DNA的最早阶段的更深入的了解，重要大气中间体的亲电性能，HI阴离子的意外稳定性以及诸如火焰和太阳大气层的能量气态环境中的碰撞阴离子破坏过程。这项广泛的研究项目的结果有望在许多科学领域都产生广泛影响。此外，该项目为研究生和本科研究专业的学生提供了高级培训机会，同时还通过Bowen博士的外展活动吸引K-12学生。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的智力优点和更广泛影响的评估来通过评估来支持的。

项目成果

Photoelectron Spectroscopic and Computational Study of the Deprotonated Gallic Acid and Propyl Gallate Anions

去质子化没食子酸和没食子酸丙酯阴离子的光电子能谱和计算研究

• DOI: 10.1021/jasms.2c00017
• 发表时间: 2022
• 期刊: Journal of the American Society for Mass Spectrometry
• 影响因子: 3.2
• 作者: Zhu, Zhaoguo;Marshall, Mary;Harris, Rachel;Collins, Evan;Bowen, Kit H.
• 通讯作者: Bowen, Kit H.

Photoelectron Spectroscopic Study of Ascorbate and Deprotonated Ascorbate Anions Using an Electrospray Ion Source and a Cryogenically Cooled Ion Trap

使用电喷雾离子源和低温冷却离子阱对抗坏血酸和去质子化抗坏血酸阴离子进行光电子能谱研究

• DOI: 10.1021/acs.jpca.1c06540
• 发表时间: 2021
• 期刊: The Journal of Physical Chemistry A
• 作者: Marshall, Mary;Zhu, Zhaoguo;Harris, Rachel;Collins, Evan;Bowen, Kit H.
• 通讯作者: Bowen, Kit H.