Sessa Francesco, Rahm Martin
Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
J Phys Chem A. 2022 Aug 18;126(32):5472-5482. doi: 10.1021/acs.jpca.2c03814. Epub 2022 Aug 8.
Controlling the distribution of electrons in materials is the holy grail of chemistry and material science. Practical attempts at this feat are common but are often reliant on simplistic arguments based on electronegativity. One challenge is knowing when such arguments work, and which other factors may play a role. Ultimately, electrons move to equalize chemical potentials. In this work, we outline a theory in which chemical potentials of atoms and molecules are expressed in terms of reinterpretations of common chemical concepts and some physical quantities: electronegativity, chemical hardness, and the sensitivity of electronic repulsion and core levels with respect to changes in the electron density. At the zero-temperature limit, an expression of the Fermi level emerges that helps to connect several of these quantities to a plethora of material properties, theories and phenomena predominantly explored in condensed matter physics. Our theory runs counter to Sanderson's postulate of electronegativity equalization and allows a perspective in which electronegativities of bonded atoms need not be equal. As chemical potentials equalize in this framework, electronegativities equilibrate.
控制材料中电子的分布是化学和材料科学的圣杯。实现这一目标的实际尝试很常见，但往往依赖于基于电负性的简单论点。一个挑战是要知道这些论点何时有效，以及哪些其他因素可能起作用。最终，电子会移动以平衡化学势。在这项工作中，我们概述了一种理论，其中原子和分子的化学势是根据对常见化学概念和一些物理量的重新解释来表达的：电负性、化学硬度以及电子排斥和核心能级相对于电子密度变化的敏感性。在零温度极限下，出现了费米能级的表达式，它有助于将这些量中的几个与凝聚态物理中主要探索的大量材料特性、理论和现象联系起来。我们的理论与桑德森的电负性均衡假设背道而驰，并提供了一种观点，即键合原子的电负性不一定相等。在这个框架中，随着化学势的平衡，电负性也会达到平衡。
