Excited State Specific Correlation Methods in Quantum Chemistry

量子化学中激发态特定关联方法

• 批准号: 2320936
• 负责人: Eric Neuscamman
• 金额: $ 53万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2320936&HistoricalAwards=false
• 关键词: Excited; State; Specific; Correlation; Methods

With support from the Chemical Theory, Models and Computational Methods program in the Division of Chemistry, Eric Neuscamman of the University of California at Berkeley is developing new tools for the computer simulation of light-driven chemistry. Whether studying DNA damage from sunlight or industrial processes that mimic photosynthesis, understanding the mechanisms by which light drives chemical change is made difficult by the tiny scales and fast pace at which the action occurs. Modern experimental techniques can offer glimpses of what is going on, but often leave key questions unanswered, such as the full series of shapes a molecule transforms itself through after absorbing energy from sunlight. The Neuscamman group will develop and deploy a new generation of computer models that faithfully simulate these processes in high priority areas of chemistry where current methods are limited. In particular, light-driven processes that move electrons from one side of a molecule to the other or that move multiple electrons at once cannot be simulated accurately by current tools except in the smallest molecules, whereas key applications of these processes occur in technological and biological settings involving hundreds of atoms. By bridging this gap, the Neuscamman group aims to deepen our understanding of light-driven chemistry and the crucial technologies that rely on it. In tandem with this research, the Neuscamman group will expand its outreach work to middle school students, teaching the underlying principles of mathematical optimization methods that support scientific priorities from chemistry to machine learning. This game-based outreach will also plant seeds around concepts like slope and curvature so that students are already familiar with exciting and lucrative real-world uses for calculus when they eventually find themselves in a calculus classroom. By engaging undergraduate students as instructors in this outreach, the activity will both broaden middle school student horizons and reinforce understanding for the active undergraduate co-worker participants. Understanding the energies of transitions in which molecules absorb light is central to chemistry. While decades of theoretical work have been dedicated to predicting the transition energies of electronic (e.g. HOMO→LUMO) excitations in particular, some categories of electronic excitation are still poorly served by available theoretical methods. Two examples of these are charge transfer states, which are central to biological and artificial light harvesting as well as many enzymatic reaction mechanisms, and double excitations, which are common in the extended π-conjugation networks of pigments and chromophores as well as in many transition metal complexes. The Neuscamman group will build on recent breakthroughs in the mean-field treatment of electronically excited states to construct what is anticipated to be a highly accurate, and affordable suite of coupled cluster and related methods for modeling electronically excited states in large molecules and molecular assemblies. These methods have the potential to significantly improve the state-of-the art in modeling both charge transfer and doubly excited states with potential broad long term scientific impacts for chemistry, biology, materials and systems chemistry.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，加州大学伯克利分校的Eric Neuscamman正在开发用于光驱动化学的计算机模拟的新工具。 无论是研究来自阳光的DNA损伤还是模拟光合作用的工业过程，理解光驱动化学变化的机制都很困难，因为这种作用发生的尺度很小，速度很快。 现代实验技术可以让我们一瞥发生了什么，但往往留下关键问题没有答案，例如分子在吸收太阳光能量后会发生一系列的形状变化。 Neuscamman小组将开发和部署新一代计算机模型，忠实地模拟当前方法有限的高优先级化学领域的这些过程。 特别是，将电子从分子的一侧移动到另一侧或同时移动多个电子的光驱动过程，除了在最小的分子中之外，无法通过当前的工具准确模拟，而这些过程的关键应用发生在涉及数百个原子的技术和生物环境中。 通过弥合这一差距，Neuscamman小组的目标是加深我们对光驱动化学和依赖于它的关键技术的理解。 在这项研究的同时，Neuscamman小组将把其推广工作扩展到中学生，教授数学优化方法的基本原理，这些方法支持从化学到机器学习的科学优先事项。 这种以游戏为基础的推广活动还将围绕斜率和曲率等概念播下种子，以便学生在最终进入微积分课堂时已经熟悉微积分令人兴奋和有利可图的现实世界用途。通过让本科生担任这一推广活动的讲师，该活动将拓宽中学生的视野，并加强对活跃的本科生同事参与者的理解。理解分子吸收光的跃迁能量是化学的核心。 虽然数十年的理论工作一直致力于预测电子（例如HOMO→LUMO）激发的跃迁能量，但某些类别的电子激发仍然没有得到有效的理论方法。 其中两个例子是电荷转移态，这是生物和人工光捕获以及许多酶促反应机制的核心，以及双激发，这在色素和发色团的扩展π共轭网络以及许多过渡金属络合物中很常见。 Neuscamman小组将建立在电子激发态的平均场处理的最新突破的基础上，以构建预期高度准确且负担得起的耦合簇和相关方法套件，用于模拟大分子和分子组装中的电子激发态。 这些方法有可能显着提高电荷转移和双激发态建模的最新技术水平，对化学，生物学，材料和系统化学具有潜在的广泛的长期科学影响。该奖项反映了NSF的法定使命，并被认为值得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来支持。