Deciphering Delocalized Bonding in Excited States, Solvated Species and Novel 0-, 1-, 2-, and 3-Dimensional Chemical Systems

在这个由NSF化学部化学结构动力学和机制（CSDM-A）计划资助的项目中，Boldyrev教授探索了多中心键合的新前沿。在高中和大学化学课上，化学键通常表现为两个原子之间共享的电子对（一对产生单键，两对产生双键，等等）。 然而，在许多情况下，化学键是通过多个原子共享电子形成的（因此称为“多中心”）。 Boldyrev教授和他的团队开发了一个理论模型，该模型考虑了两中心和多中心化学键。 他和他的团队现在正在应用这个模型来解释复杂系统的几何和行为，例如包含数十个原子的簇分子，溶解在液体中的分子以及被光激发的分子。 化学键是化学理解的核心，是解释为什么分子和固体采用某种几何结构，以及为什么分子或固体以特定方式与其他分子反应的基础。 Boldyrev教授的计算方法被称为自适应自然密度分区（AdNDP）。“AdNDP目前被世界各地的50个研究小组使用，Boldyrev小组将继续向其他科学家提供该程序及其更新。 参与该项目的研究生不仅有助于推动化学领域的发展，而且还获得了计算机编程和软件开发的重要技能，所有这些都是技术行业的宝贵资产。该项目正在探索AdNDP方法及其固态自适应（SSAdNDP）应用的新化学前沿。 研究的课题包括分子和团簇激发态的化学键，溶剂化电子和多电荷阴离子与溶剂分子的相互作用。 该项目旨在了解在极高压力下合成的新型三维（3D）化学系统中的化学键合。这种高压化合物违反了许多传统的化学计量和化学键。 在这样的系统中，化学键不能仅根据刘易斯模型来合理化。该项目继续受益于与实验学家（约翰霍普金斯大学的Kit Bowen教授，布朗大学的王来胜教授，埃默里大学的Michael Heaven教授和中国科学院的孙忠明教授）的合作，他们提供了新制造的簇（0D物种）以及新的1D，2D和3D材料的实验数据。这项工作的更广泛的影响，包括潜在的社会效益的AdNDP和SSAdNDP方法的合理设计的新材料，并在化学教育中的应用。这些方法和软件的支持下开发的化学结构动力学和机制（CSDM-A）计划的NSF化学部正在开发中使用的类，如普通化学，计算化学，量子化学，先进的无机化学，纳米技术和材料化学。

In this project funded by the Chemical Structure Dynamics and Mechanism (CSDM-A) Program of the NSF Chemistry Division, Professor Boldyrev explores new frontiers for multicenter bonding. In high school and college chemistry classes, chemical bonds are typically presented as pairs of electrons shared between two atoms (a single pair produces a single bond, two pairs create a double bond, etc.). However, there are many cases where chemical bonds are formed through electrons being shared by multiple atoms (hence the name "multicenter"). Professor Boldyrev and his group have developed a theoretical model that takes into account both two- and multi-center chemical bonding. He and his group are now applying this model to explain the geometry and behavior of complex systems such as cluster molecules containing dozens of atoms, molecules dissolved in liquids, and molecules which have been excited by light. Chemical bonding is at the heart of chemical understanding, and is the basis for explaining why molecules and solids adopt a certain geometric structure, and why molecules or solids react with other molecules in a particular manner. Professor Boldyrev's computational approach is called Adaptive Natural Density Partitioning, or "AdNDP." AdNDP is currently used by 50 research groups around the world, and the Boldyrev group is continuing to make this program and its updates available to other scientists. The graduate students involved in this project are not only helping to advance the field of chemistry, but are also obtaining important skills in computer programming and software development, all of which are valuable assets in the technology industry.This project is exploring new chemistry frontiers for the application of the AdNDP method and its solid-state adaptation (SSAdNDP). The topics being studied include chemical bonding in excited states of molecules and clusters, the interaction of solvated electrons and multiply charged anions with solvent molecules. The project seeks to understand the chemical bonding in novel three-dimensional (3D) chemical systems that have been synthesized under extremely high pressure. Such high-pressure compounds violate many conventional stoichiometries and chemical bonding. In such systems, chemical bonding cannot be rationalized on the basis of a Lewis model alone. This project continues to benefit from collaborations with experimentalists (Professors Kit Bowen at Johns Hopkins, Lai-Sheng Wang at Brown University, Michael Heaven at Emory University, and Zhong-Ming Sun at the Chinese Academy of Sciences) who are providing experimental data on newly made clusters (0D species), as well as new 1D-, 2D- and 3D-materials. The broader impacts of this work include potential societal benefits of the AdNDP and SSAdNDP methods for the rational design of new materials, and for application in chemical education. These methods and the software developed under the support of Chemical Structure Dynamics and Mechanism (CSDM-A) Program of the NSF Chemistry Division are being developed for use in classes such as general chemistry, computational chemistry, quantum chemistry, advanced inorganic chemistry, nanotechnology, and materials chemistry.