CAREER: State-of-the-art Quantum Calculations on a Novel Class of Super-atoms: Discovering Exotic Chemical Bonding Schemes and Proposing New Two and Three Dimensional Materials

现代工业对新材料的需求量很大。特别需要新的方法来制造电池和其他电子产品。一种新材料可以通过溶解在液氨中的金属原子的相互作用形成。在一个正常的原子中，带负电的电子围绕带正电的中心原子核旋转。在这个由化学系化学结构动力学和机制（CSDM-A）项目资助的项目中，奥本大学的Evangelos Miliordos教授正在研究浓金属氨溶液，其中来自金属原子的电子远离原子核移动，它围绕附近氨分子的最外边缘运行。金属原子和氨分子形成一个大的组合结构，其中分子的原子就像单个超大原子的原子核。Miliordos教授正在应用量子力学原理研究单个金属氨分子的物理和化学性质。这些理论研究的知识可以用来指导这类独特的化学品的实验，这类化学品被称为溶剂化电子前体（SEP）。未来的应用可能在电池/太阳能电池，催化和量子计算的化学。参与该项目的学生学习现代计算化学方法，成为过渡金属化学专家。Miliordos教授还在根据研究成果开发模块，这些模块将向高中生介绍这些开创性的概念，该项目侧重于高水平电子结构计算的性能（密度泛函理论，多参考组态相互作用，微扰理论和耦合簇方法）与一些氨，胺，多胺，或其它配体。当配体接近金属中心时，它们将一些金属价电子置换到络合物的外围，从而形成束缚的里德伯分子系统。扩散电子占据以金属-氨核为中心的类氢轨道。在最低能态下，s-、p-、d-、f-和g-形轨道在类似于Jeldom或核壳模型的壳模型中被识别：1 s、1 p、1d、2s、2 p、1f、2d、3s和1g。地面和几个低的电子状态的电子配置进行了研究和精确的激发能计算，以解释现有的和协助未来的实验研究。这些过渡金属配合物的稳定性进行检查，在金属配体的结合能和活化能朝向释放分子氢。这项工作的更广泛的影响包括从过渡金属化学的理解增加潜在的社会效益，以及为学生提供培训的机会，在使用和批判性选择现有的电子结构techniques.This award reflects NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

New materials are in high demand in modern industry. There is a particular need for new approaches to building batteries and other electronics. One type of new material may be formed through the interaction of metal atoms dissolved in liquid ammonia. In a normal atom, negatively charged electrons orbit around a positively charged central nucleus. In this project funded by the Chemical Structure Dynamics and Mechanism (CSDM-A) program of the Chemistry Division, Professor Evangelos Miliordos of Auburn University is studying concentrated metal-ammonia solutions, where an electron from the metal atom moves so far from the nucleus that it orbits the outermost edge of a nearby ammonia molecule. The metal atom and ammonia molecule form a large combined structure, where the atoms of the molecule act like the nucleus of a single super-sized atom. Professor Miliordos is applying the principles of quantum mechanics to study the physical and chemical properties of individual metal-ammonia molecules. The knowledge from these theoretical studies can be used to guide experiments on this unique class of chemicals, which are known as solvated electron precursors (SEP). Future applications are possible in the chemistry of batteries/solar cells, catalysis, and quantum computing. Students engaged in the project learn modern computational chemistry methods and become experts in transition metal chemistry. Professor Miliordos is also developing modules based on the research results that will introduce these groundbreaking concepts to high school students.The project focuses on the performance of high-level electronic structure calculations (density functional theory, multi-reference configuration interaction, perturbation theory, and coupled cluster approaches) of the properties of transition metals coordinated with a number of ammonia, amine, polyamine, or other ligands. As the ligands approach the metal center, they displace some of the metallic valence electrons to the periphery of the complex making bound Rydberg molecular systems. The diffuse electrons occupy hydrogenic-type orbitals centered around the metal-ammonia core. In the lowest energy states s-, p-, d-, f-, and g-shaped orbitals are identified within a shell model resembling that of the Jellium or nuclear-shell models: 1s, 1p, 1d, 2s, 2p, 1f, 2d, 3s, and 1g. The electronic configuration for the ground and several low-lying electronic states is investigated and accurate excitation energies are calculated to explain existing and assist future experimental studies. The stability of these transition metal complexes is examined in terms of metal-ligand binding energies and activation energies towards the release of molecular hydrogen. The broader impacts of this work include potential societal benefits from an increased understanding of transition metal chemistry, as well as opportunities for the training of students in the use and critical selection of the existing electronic structure techniques.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.