CAREER: Resonant Hartree-Fock Inspired Descriptions of Excited State Processes

在化学系化学理论、模型和计算方法（CTMC）项目和刺激竞争研究既定项目（EPSCoR）的支持下，路易斯维尔大学的Lee M. Thompson正在开发计算方法来模拟与金属光催化相关的激发态过程。金属光催化结合了过渡金属催化和光氧化还原催化，实现了新的分子合成方法。然而，催化剂活化的几种相互竞争的机制可能导致不同的反应产物，因此计算模型有助于建立激发态过程的速率和设计催化系统，以提高期望的反应活性。为此，存在建模挑战，包括：(i)所涉及系统的大小，（ii）这些系统的电子结构的性质，因为这些系统通常不适合当前包含在减少cpu（中央处理器）时间方法中的近似，以及（iii）需要计算难以从模拟中提取的术语的理论形式化。为了解决这些困难，汤普森博士正在开发一种计算方法，将低成本的近似值结合在一起，每个近似值捕获电子结构的不同特征。目的是开发一个更精确的方法的通用计算平台，利用电子相互作用的划分来减少计算工作量。该项目还包括制定一项综合教育计划，重点关注编程素养和可持续软件开发，旨在为学生提供对物理化学和计算科学的更深入理解。首席研究员还致力于建立一个论坛，通过德比系列讲座吸引肯塔基州路易斯维尔化学企业的利益相关者。这个关于共振哈特里-福克启发的激发态过程描述的项目包括两个主要的科学目标。首先，Thompson研究团队正在开发探索自洽场（SCF）解空间的算法，以了解SCF功能景观如何编码不同的相关机制。该方法允许枚举SCF解，从中可以选择跨越分子系统中存在的相关机制的短行列式展开。此外，SCF解决方案可以用作后SCF方法的参考。其次，优化不同构型不同轨道波函数的模型正在设计和实现，以解释不同相关机制之间的相互作用。由此产生的波函数被用作平台，以减少计算成本来恢复剩余的相关能量。这些新方法将应用于金属光催化体系中光致电子转移和激发能转移速率的研究。这些工具，如果成功的话，可能会对新的光氧化还原催化剂系统和过程的设计产生重大影响，这是当前反应发展中非常感兴趣的领域。该奖项反映了美国国家科学基金会的法定使命，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，被认为值得支持。

With support from the Chemical Theory, Models and Computational Methods (CTMC) Program in the Division of Chemistry and the Established Program to Stimulate Competitive Research (EPSCoR), Lee M. Thompson of University of Louisville is developing computational approaches to simulate excited state processes of relevance to metallo-photocatalysis. Metallo-photocatalysis combines transition metal catalysis and photoredox catalysis to enable new molecular synthesis approaches. However, several competing mechanisms for catalyst activation can potentially lead to different reaction products, and so computational modelling is beneficial to establish the rates of excited state processes and design catalytic systems that enhance the desired reactivity. For this, modeling challenges exist, including: (i) the size of the systems involved, (ii) the nature of the electronic structure of these systems as these are often not amenable to current approximations embodied in reduced-CPU (central processing unit) time methods, and (iii) theoretical formalisms requiring computation of terms that are difficult to extract from simulation. To resolve these difficulties, Dr. Thompson is developing computational methods that couple together low-cost approximations that each capture different features of the electronic structure. The aim is to develop a general computational platform of more accurate approaches that takes advantage of partitioning of the electronic interactions to reduce computational efforts. This project also includes the development of an integrated education plan focusing on programming literacy and sustainable software development that aims to provide students with a deeper understanding of physical chemistry and computational science. The principal investigator is also working to build a forum to engage stakeholders in the chemistry enterprise in Louisville, KY through the Derby lecture series. This project on Resonant Hartree-Fock inspired descriptions of excited state processes consists of two main scientific goals. First, the Thompson research team is developing algorithms that explore self-consistent field (SCF) solution space to understand how the SCF function landscape encodes different correlation mechanisms. The methods permit enumeration of SCF solutions from which a short determinant expansion can be chosen that spans relevant correlation mechanisms present in molecular systems. Additionally, the SCF solutions can be used as references for post-SCF methods. Second, models that optimize a different-orbitals-for-different-configurations wavefunction to account for interactions between the different correlation mechanisms are being designed and implemented. The resulting wavefunction is being used as a platform to recover remaining correlation energy at reduced computational cost. The new methods will be applied to the study of photo-induced electron transfer and excitation energy transfer rates in metallo-photocatalytic systems. These tools, if successful, could have a significant impact on the design of new photoredox catalyst systems and processes, an area of great current interest in reaction development.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.