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.

在化学理论，模型和计算方法计划的支持下，路易斯安那大学东南大学的托马斯·索默菲尔德教授将建模临时分子阴离子。由赞助电子发射衰减的带负电荷的分子离子称为临时阴离子，因为它们显示出类似于其他物种的寿命。临时阴离子不能形成稳定的化合物，但它们作为许多自然和技术过程中的关键中间体出现，包括等离子体蚀刻，大气化学，对生物组织的辐射损害和癌症治疗。建模临时阴离子比稳定分子的建模更具挑战性。 Sommerfeld博士及其小组旨在模拟描述包括即将发出电子的临时阴离子的所有电子设备的量子机械方程。 Sommerfeld教授将致力于开发可靠的，具有成本效益的模型，以计算临时阴离子的寿命，这是更粗糙的模拟的关键参数。此外，Sommerfeld博士的小组将采用开发的方法来帮助解释印第安纳大学Chick Jarrold博士的小组衡量的照片解决光谱。由于东南部是位于传统低收入状态的粗糙，低收入地区的PUI（主要是本科机构），并且由于该研究将与本科成员一起进行，因此对the-Job培训的影响及其对研究基础设施的访问将是重要的。图案实验。 Sommerfeld博士将将其系统方法比较的框架从模型电位扩展到电子结构世界，以及从l²方法到投影操作员方法。共振方法至少结合了五个方面：连续方法，电子结构方法，价基础，分散基础和数据分析。由于输入这些计算的大量因素，比较受到挑战，Sommerfeld博士将集中于对持续方法的无偏比较。为此，Sommerfeld博士将在开源PSI4软件包中实施对称性的限制潜力。 Sommerfeld博士将使用新的和传统的方法来通过阐明初始状态分布，识别短暂的中间体并提出机制来帮助解释照片解决光谱。 Sommerfeld小组的这些研究具有广泛的科学影响。最重要的是，开发用于比较连续方法的系统框架和PSI4中基于限制的潜在方法对临时阴离子电子结构领域的研究界对研究社区有益。该奖项反映了NSF的法定任务，并通过使用该基金会的知识分子和更广泛的影响来评估NSF的法定任务。

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