Toward an Experimental Quantum Chemistry: Exploring a New Energy Partitioning

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• 作者：Martin Rahm ; Roald Hoffmann
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：August 19, 2015
• 年：2015
• 卷：137
• 期：32
• 页码：10282-10291
• 全文大小：490K
• ISSN：1520-5126

文摘

Following the work of L. C. Allen, this work begins by relating the central chemical concept of electronegativity with the average binding energy of electrons in a system. The average electron binding energy, 蠂虆, is in principle accessible from experiment, through photoelectron and X-ray spectroscopy. It can also be estimated theoretically. 蠂虆 has a rigorous and understandable connection to the total energy. That connection defines a new kind of energy decomposition scheme. The changing total energy in a reaction has three primary contributions to it: the average electron binding energy, the nuclear鈥搉uclear repulsion, and multielectron interactions. This partitioning allows one to gain insight into the predominant factors behind a particular energetic preference. We can conclude whether an energy change in a transformation is favored or resisted by collective changes to the binding energy of electrons, the movement of nuclei, or multielectron interactions. For example, in the classical formation of H₂ from atoms, orbital interactions dominate nearly canceling nuclear鈥搉uclear repulsion and two-electron interactions. While in electron attachment to an H atom, the multielectron interactions drive the reaction. Looking at the balance of average electron binding energy, multielectron, and nuclear鈥搉uclear contributions one can judge when more traditional electronegativity arguments can be justifiably invoked in the rationalization of a particular chemical event.