CAREER: EXTENDING GROUND STATE QUANTUM CHEMISTRY TO EXCITED STATES

加州大学伯克利分校的Eric Neuscamman获得了化学系化学理论、模型和计算方法项目的一项奖项的支持，以开发新的理论模型来描述光吸收激发的分子。 与光的相互作用是化学的基础。 例如，激光在分子诊断中发挥着核心作用。光的吸收及其转化为电能是太阳能和许多用于防范化学和生物威胁的传感器的核心。科学家们仍然无法回答许多关于吸收光的分子行为的关键问题。 通过构建理论模型来描述光激活分子，Neuscamman的研究提供了补充和增强实验方法的见解。 Neuscamman还在建立多层次的外联和教育工作。 他的计划使用边玩边学和边教边学的原则来改进K-12教育中的数值优化概念和方法。这项工作的重点是设计和部署适合年龄的游戏，例如为高中生编写“自己的虚拟机器人程序”。这种外联的一个主要特点是纵向一体化，即招收年龄较大的学生，特别是本科生和高中生参加针对年龄较小学生的外联工作，从而实现边教边学。总之，这些努力使学生在数值方法思维和现实世界的应用程序，为他们准备正式的微积分培训，并为他们提供所需的数学技能，为科学工作的领先优势。基态变分原理是量子化学中最重要的理论工具，它允许波函数近似及其轨道形状为特定分子的基态量身定制。 从历史上看，由于缺乏激发态的类似工具，各种化学过程的建模一直受到阻碍。 这种激发态在理解光收集、大气过程和能量储存方面发挥着核心作用。 虽然量子蒙特卡罗方法能够直接与严格的激发态变分原理，他们有重要的局限性，并没有，目前，受益于相同的量子蒙特卡罗/量子化学协同作用存在的基态。 Neuscamman教授正在将激发态变分原理的优势扩展到传统量子化学的生态系统中。 这个项目开始于一个激发态特定的平均场理论，这是一个直接推广的哈特里福克理论。Neuscamman教授正在开发新的激发态相关理论，如M 'ller Plesset理论和耦合簇理论。 这些方法既是Monte Carlo方法的天然伙伴，也是其自身的强大工具。 总之，Neuscamman的工作概括了量子蒙特卡罗世界之外的激发态变分原理，以便将传统的基态量子化学应用于激发态问题。该奖项反映了NSF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。

Eric Neuscamman of the University of California, Berkeley is supported by an award from the Chemical Theory, Models and Computational Methods Program in the Division of Chemistry to develop new theoretical models to describe molecules that are excited by the absorption of light. Interactions with light are fundamental to chemistry. Lasers, for example, play a central role in molecular diagnostics. The absorption of light and its conversion to electricity is central to solar power and to many of the sensory devices used to guard against chemical and biological threats. Scientists are still unable to answer many critical questions about the behavior of molecules that have absorbed light. By constructing theoretical models to describe light-activated molecules, Neuscamman's research provides insights that complement and enhance experimental methods. Neuscamman is also building a multi-level outreach and education effort. His program uses learn-by-playing and learn-by-teaching principles to improve numerical optimization concepts and methods across K-12 education. This effort centers around the design and deployment of age-appropriate games, such as "program your own virtual robot" for high school students. A key feature of this outreach is vertical integration, in which older students, especially undergraduates and high school students, are recruited into the outreach efforts targeting younger students, thus enabling learning-by-teaching. Together, these efforts give students a head start in numerical methods thinking and real-world applications that prepare them for formal calculus training and provide them with the required mathematical skills for scientific endeavors. The ground state variational principle is the single most important theoretical tool in quantum chemistry, allowing wave function approximations and their orbital shapes to be tailored for the ground state of a specific molecule. Historically, the modeling of a large variety of chemical processes has been hampered by the lack of analogous tools for excited states. Such excited states play central roles in understanding light harvesting, atmospheric processes, and energy storage. Although quantum Monte Carlo methods are able to work directly with rigorous excited state variational principles, they have important limitations and do not, at present, benefit from the same quantum-Monte-Carlo/quantum-chemistry synergies that exist for ground states. Professor Neuscamman is extending the advantages of excited state variational principles into the ecosystem of traditional quantum chemistry. This project begins with an excited-state-specific mean field theory that is a direct generalization of Hartree Fock Theory. Professor Neuscamman is developing new excited state generalizations of correlation theories like M'ller Plesset theory and coupled cluster theory. These methods act both as natural partners for Monte Carlo methods and as powerful tools in their own right. In summary, Neuscamman's work generalizes excited state variational principles beyond the world of quantum Monte Carlo in order to bring traditional ground state quantum chemistry to bear on excited state problems.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.