RUI: Characterizing Valence, Temporary, and Non-valence Anions: Computational Methods and Photo-detachment Spectroscopy

RUI：表征化合价、临时和非化合价阴离子：计算方法和光分离光谱

• 批准号: 2303652
• 负责人: Thomas Sommerfeld
• 金额: $ 15.23万
• 依托单位: Southeastern Louisiana University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2303652&HistoricalAwards=false
• 关键词: RUI; Characterizing; Valence; Temporary; Non

With support from the Chemical Theory, Models and Computational Methods program in the Division of Chemistry, Professor Thomas Sommerfeld of Southeastern Louisiana University will model temporary molecular anions. Negatively charged molecular ions that decay by spontaneous electron emission are called temporary anions as they show lifetimes similar to other species. Temporary anions cannot form stable compounds, but they occur as critical intermediates in many natural and technical processes including plasma etching, atmospheric chemistry, radiation damage to living tissue, and cancer therapy. Modeling temporary anions is far more challenging than modeling of stable molecules. Dr. Sommerfeld and his group aim to simulate the quantum mechanical equations describing all electrons of the temporary anion including the outgoing electron. Professor Sommerfeld will work to develop reliable, cost-efficient models to compute the lifetime of temporary anions, a critical parameter for more coarse-grained simulations. Moreover, Dr. Sommerfeld’s group will apply the developed methods to aid with the interpretation of photo-detachment spectra measured by Dr. Chick Jarrold’s group at Indiana University. Since Southeastern is a PUI (predominantly undergraduate institution) located in a rural, low-income region of a traditionally low-income state, and since the research will be conducted with undergraduate group members, the impact on disadvantaged students and their access to the research infrastructure is expected to be significant.Under this award, Professor Thomas Sommerfeld and his group will combine method development for resonance states with the study of photo-detachment experiments. Dr. Sommerfeld will extend his framework for systematic method comparison from model potentials into the electronic structure world and from L²-methods to projection-operator approaches. Methods for resonances combine at least five aspects: a continuum approach, an electronic structure method, a valence basis, a diffuse basis, and a data analysis. Owing to the large number of factors entering these calculations, comparisons are challenging, and Dr. Sommerfeld will focus on an unbiased comparison of continuum methods. For this purpose, Dr. Sommerfeld will implement symmetry-conforming confinement potentials into the open-source Psi4 package. Dr. Sommerfeld will use the new and traditional methods to aid in the interpretation of photo-detachment spectra by elucidating initial state distributions, identifying short-lived intermediates, and suggesting mechanisms. These studies from the Sommerfeld group have the potential for broad scientific impact; most importantly, the development of a systematic framework for comparing continuum methods and the confinement potential based methods in Psi4 would be beneficial for the research community in the area of temporary anion electronic structure.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.

在化学系化学理论、模型和计算方法项目的支持下，东南路易斯安那大学的 Thomas Sommerfeld 教授将对通过自发电子发射衰变的带负电的分子离子进行建模，因为它们的寿命相似，因此被称为临时阴离子。临时阴离子不能形成稳定的化合物，但它们在许多自然和技术过程中作为关键中间体出现，包括等离子体蚀刻、大气化学、对活体组织的辐射损伤和癌症治疗。索末菲博士和他的团队的目标是模拟描述临时阴离子（包括传出电子）的所有电子的量子力学方程，这比稳定分子的建模更具挑战性。临时阴离子是更粗粒度模拟的关键参数。此外，Sommerfeld 博士的团队将应用开发的方法来帮助解释印第安纳州 Chick Jarrold 博士团队测量的光脱离光谱。由于东南大学是一所 PUI（主要是本科院校），位于传统低收入州的农村低收入地区，并且由于该研究将与本科生小组成员一起进行，因此对弱势学生及其入学机会的影响研究基础设施预计将非常重要。根据该奖项，Thomas Sommerfeld 教授和他的团队将把共振态的方法开发与光分离实验的研究结合起来。Sommerfeld 博士将把他的系统方法比较框架从模型势扩展到。电子结构世界和从 L² 方法到投影算子方法，共振方法至少结合了五个方面：连续介质方法、电子结构方法、价态基础、扩散基础和数据分析。计算、比较具有挑战性，索末菲博士将重点关注连续介质方法的无偏比较。为此，索末菲博士将在开源中实现符合对称性的限制势。 Sommerfeld 博士将使用新的和传统的方法通过阐明初始态分布、识别短暂的中间体并提出机制来帮助解释光脱离光谱。Sommerfeld 小组的这些研究具有广泛的潜力。科学影响；最重要的是，开发一个用于比较连续介质方法和 Psi4 中基于限制势的方法的系统框架将有利于临时阴离子电子结构领域的研究界。该奖项反映了通过使用基金会的智力价值和更广泛的影响审查标准进行评估，NSF 的法定使命被认为值得支持。

项目成果

Use of bound state methods to calculate partial and total widths of shape resonances

使用束缚态方法计算形状共振的部分宽度和总宽度

• DOI: 10.1039/d3cp04154a
• 发表时间: 2023
• 期刊: Physical Chemistry Chemical Physics
• 影响因子: 3.3
• 作者: Falcetta, Michael F.;Fair, Mark C.;Slimak, Stephen R.;Jordan, Kenneth D.;Sommerfeld, Thomas
• 通讯作者: Sommerfeld, Thomas