Bonding Analysis of Ab Initio Electronic Wave Functions in Molecules

分子中从头算电子波函数的键合分析

• 批准号: 1147446
• 负责人: Klaus Ruedenberg
• 金额: $ 43.5万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-05-01 至 2016-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1147446&HistoricalAwards=false
• 关键词: Bonding; Analysis; Ab; Initio; Electronic

Klaus Ruedenberg and Mark Gordon of Iowa State university are supported by an award from the Chemical Theory, Models and Computational Methods program in the Chemistry division to develop a general method for resolving the bond energies in any molecule and between interacting molecules in terms of contributions that arise from the deformations of the individual atoms and from the interactions between different atoms. The latter are furthermore resolved in terms of contributions that are attributed to distinct physical interactions, viz. quasi-classical electrostatic interactions, interference interactions and charge transfer effects. The analysis is extracted from the accurate ab initio energy expression by transformation into a basis of quasi-atomic orbitals that are intrinsically deduced from the accurate ab initio wave function. The role of the various contributions and of their kinetic and potential energy components in the establishment of chemical bonding is investigated for a number of reactions. On this basis, conceptual characterizations of bonding are identified and a rigorous ab initio basis for similarities and distinctions between different bonding patterns is established.Current quantum chemistry can generate quantitative information and predictions that are valuable and useful in many areas of chemical work and that the purely experimental approach is unable to supply. These capabilities are the result of advances in mathematical algorithms in conjunction with the steady increase in the speed and storage capacity of electronic computers. The increasing complexity of the computational techniques has made it, however, extremely difficult to perceive the physical reasons why bonds form and break between atoms, even in simple and fundamental chemical reactions. This lack of physical insight has created a large gap between the number crunching approach and the chemical intuition that has served experimental chemists well for two centuries, and the bridging between the two has proved to be nontrivial. The present work identifies the physical contents of these complex calculations and extracts an interpretation of chemical bonding that can fit into the intuitive frame work of chemical reasoning. Previously untapped chemically interesting information, which is imbedded in accurate quantum mechanical computations, is made accessible.

爱荷华州立大学的克劳斯·鲁登伯格和马克·戈登获得了化学学部化学理论、模型和计算方法项目的奖励，他们开发了一种通用的方法，可以根据单个原子的变形和不同原子之间的相互作用产生的贡献，来解决任何分子和相互作用分子之间的键能。后者进一步解决了由于不同的物理相互作用，即准经典静电相互作用，干涉相互作用和电荷转移效应的贡献。该分析是由精确的从头算能量表达式转化为准原子轨道的基础，而准原子轨道是由精确的从头算波函数推导出来的。对一些反应的各种贡献及其动能和势能组分在化学键建立中的作用进行了研究。在此基础上，确定了键的概念特征，并为不同键模式之间的相似性和区别建立了严格的从头算基础。目前的量子化学可以产生定量信息和预测，这些信息和预测在化学工作的许多领域都是有价值和有用的，这是纯实验方法无法提供的。这些能力是数学算法的进步与电子计算机速度和存储容量的稳步增长相结合的结果。然而，随着计算技术的日益复杂，即使是在简单和基本的化学反应中，也很难理解原子之间键形成和断裂的物理原因。由于缺乏物理洞察力，在数字运算方法和两个世纪以来一直为实验化学家服务的化学直觉之间造成了巨大的差距，而这两者之间的桥梁已被证明是重要的。目前的工作确定了这些复杂计算的物理内容，并提取了一种可以适合化学推理的直观框架的化学键的解释。以前未开发的化学有趣信息，嵌入在精确的量子力学计算中，是可以访问的。