Quantum Chemistry Methods for Excited States at Liquid- and Solid-State Interfaces

约翰·M.俄亥俄州州立大学的赫伯特得到了化学系化学理论、模型和计算方法项目的一个奖项的支持，该项目旨在开发分子如何相互作用的分子级计算机模型。 该研究涉及水滴表面的化学，水滴是大气化学反应的主要媒介。 这些研究还检查了半导体光催化剂的表面，这些光催化剂是进行“人工光合作用”的有前途的材料，即以化学键储存太阳能。 赫伯特教授开发的理论方法，联合收割机与新兴的激光光谱实验技术相结合，以表征复杂的系统。 赫伯特教授的理论计算回答了关于金属氧化物光催化剂的效率极限以及表面水分子的化学反应性如何不同于内部水分子的基本问题。 作为这项工作的一部分开发的新的理论和计算工具将被纳入QChem软件包，该软件包广泛用于化学教育和高通量计算工作，如哈佛清洁能源项目和电解质基因组项目。此外，这项工作的一个关键部分是开发计算机程序之间的接口，该接口可免费提供给超级计算机中心，其中包括俄亥俄州内的所有学院和大学（主要包括本科生和非博士生）。授予机构）通过俄亥俄州超级计算机中心。这项工作将把新的软件工具到实践化学家手中。赫伯特教授正在开发量子化学方法，可以描述复杂系统的激发态，特别关注界面现象。 这些方法是“QM：QM”嵌入的例子，使用高级电子结构方法（相关波函数或混合密度泛函）来描述激发态，使用低级方法（周期密度泛函理论）来描述环境。 两种类型的界面现象被认为是：在空气/水界面，其光谱可以提供一个敏感的分子探针的结构，该接口和过渡金属氧化物光催化剂的兴趣，水裂解，其中的目标是了解极化子自陷动力学限制催化效率的溶剂化电子的光化学生成。 这项研究与新兴的光谱技术密切相关，包括使用液体微射流探测空气/水界面的表面敏感紫外光谱和研究光催化材料的电荷载流子动力学的飞秒瞬态XUV光谱。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知识价值和更广泛的影响审查标准进行评估来支持。

Professor John M. Herbert of The Ohio State University is supported by an award from the Chemical Theory, Models and Computational Methods program in the Division of Chemistry to develop molecular-level computer models of how molecules interact with each other. The research addresses chemistry at the surface of water droplets, which are the primary medium of atmospheric chemical reactions. The studies also examine the surface of semiconductor photocatalysts that are promising materials to conduct “artificial photosynthesis”, that is, the storage of solar energy in chemical bonds. Professor Herbert develops theoretical methods that combine with emerging experimental techniques in laser spectroscopy to characterize complex systems. Professor Herbert’s theoretical calculations answer fundamental questions regarding the efficiency limits of metal oxide photocatalysts as well as how the chemical reactivity of surface water molecules differ from that of interior water molecules. New theoretical and computational tools developed as part of this work will be incorporated into the QChem software package, which is widely used in chemical education and in high-throughput computational efforts such as the Harvard Clean Energy Project and the Electrolyte Genome Project. Furthermore, a crucial part of this work is the development of an interface between computer programs that is made freely available to supercomputer centers, which includes all colleges and universities within Ohio (including primarily undergraduate and non-Ph.D.-granting institutions) through the Ohio Supercomputer Center. This work will put new software tools into the hands of practicing chemists. Professor Herbert is developing quantum chemistry methods that can describe excited states of complex systems, with specific focus on interfacial phenomena. These methods are examples of “QM:QM” embedding, using high-level electronic structure methods (correlated wave functions or hybrid density functionals) to describe excited states and lower-level methods (periodic density functional theory) to describe the environment. Two types of interfacial phenomena are considered: photochemical generation of solvated electrons at the air/water interface, whose spectroscopy may offer a sensitive molecular probe of the structure of that interface and transition metal oxide photocatalysts of interest for water splitting, where the goal is to understand the polaron self-trapping dynamics that limit catalytic efficiency. This research is closely aligned with emerging spectroscopic techniques, including surface-sensitive UV spectroscopy using liquid microjets to probe the air/water interface and femtosecond transient XUV spectroscopy to study charge-carrier dynamics of photocatalytic materials.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.