Non-Born-Oppenheimer Effects in the Framework of Multicomponent Time-Dependent Density Functional Theory

耶鲁大学的Sharon Hammes-Schiffer得到了化学部化学理论、模型和计算方法计划的支持，该计划开发计算方法来研究化学体系中电子和质子之间的相互作用。电子和质子之间的耦合在光合作用和呼吸作用等许多重要的生物过程中起着至关重要的作用。它们还在技术方面发挥作用，例如，在太阳能电池的能源生产方面。开发精确描述这种耦合的计算方法是具有挑战性的。电子和质子都很轻，必须用量子力学来处理。Hammes-Schiffer和她的同事开发了计算效率很高的量子力学方法。这些方法适用于与生物和化学相关的特定过程。Hammes-Schiffer研究小组还维护和改进了一个网站，其中包含与这一主题有关的软件和教育工具。本网站上提供的计算机程序、工具、演示和教程将使各个领域的科学家能够了解这一主题。此外，该项目通过更好地了解电子和质子之间的耦合，促进了技术和生物医学的进步。一个重要的例子是设计更有效的太阳能电池和其他替代的可再生能源。另一个例子是通过修饰依赖于电子和质子之间耦合的酶来设计更有效的药物。该项目的目标是开发新的理论和计算方法，以深入了解光诱导质子转移和质子耦合电子转移(PCET)反应的基本原理，这些反应在广泛的生物和化学过程中发挥着至关重要的作用。要审查的具体问题包括核量子效应的作用，如质子离域和零点能量，以及非Born-Oppenheimer效应，这些效应在这些类型的反应中往往很重要。方法的发展是在核-电子轨道密度泛函理论(NEO-DFT)的框架内进行的，该方法在DFT框架内从量子力学的角度处理关键核，如转移质子(S)和电子。重点是发展多组分含时密度泛函(NEO-TDDFT)方法来计算电子激发态、质子振动态和电子-质子振子态。用这种方法计算了光致质子转移和PCET体系的激发能和跃迁密度。正将NEO-DFT和NEO-TDDFT方法纳入公开提供的电子结构资料包中。此外，正在编写教程，解释如何进行近地天体计算，并强调这一方法的独特能力。此外，一个关于PCET的网站正在得到加强，以向社区传达有用的信息，并提供与研究PCET相关的有用工具、脚本和程序。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Sharon Hammes-Schiffer of Yale University is supported by an award from the Chemical Theory, Models and Computational Methods program in the Division of Chemistry to develop computational approaches to study the interaction between electrons and protons in chemical systems. The coupling between electrons and protons plays a vital role in many important biological processes such as photosynthesis and respiration. They also play a role in technology, for example, in energy production in solar cells. Developing computational methods to accurately describe this coupling is challenging. Electrons and protons are so light that they must be treated quantum mechanically. Hammes-Schiffer and her coworkers develop quantum mechanics methods that are computationally efficient. These methods are applied to specific processes of biological and chemical relevance. The Hammes-Schiffer research group also maintains and enhances a website containing software and educational tools related to this topic. The computer programs, tools, demonstrations, and tutorials available on this web site will enable scientists in a broad range of fields to learn about this topic. In addition, this project facilitates technological and biomedical advances through a better understanding of the coupling between electrons and protons. An important example is the design of more effective solar cells and other alternative, renewable energy sources. Another example is the design of more effective drugs through modification of enzymes that rely on the coupling between electrons and protons. The objective of this project is to develop new theoretical and computational approaches that will provide insight into the underlying fundamental principles of photoinduced proton transfer and proton-coupled electron transfer (PCET) reactions, which play a vital role in a broad range of biological and chemical processes. The specific issues to be examined include the roles of nuclear quantum effects, such as proton delocalization and zero-point energy, as well as non-Born-Oppenheimer effects, which are often significant in these types of reactions. The method development is conducted within the framework of the nuclear-electronic orbital density functional theory (NEO-DFT) approach, which treats key nuclei, such as the transferring proton(s), quantum mechanically on the same level as the electrons within the framework of DFT. The focus is to develop the multicomponent time-dependent DFT (NEO-TDDFT) approach for calculating excited electronic, proton vibrational, and electron-proton vibronic states. This approach is used to compute excitation energies and transition densities for photoinduced proton transfer and PCET systems. The NEO-DFT and NEO-TDDFT approaches is being incorporated into a publicly available electronic structure package. In addition, tutorials are being created to explain how to perform NEO calculations and to highlight the unique capabilities of this approach. Furthermore, a web site on PCET is being enhanced to convey useful information to the community and to provide useful tools, scripts, and programs relevant to studying PCET.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.