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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >On the foundations of chemical reactivity theory
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On the foundations of chemical reactivity theory

机译：关于化学反应性理论的基础

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In formulating chemical-reactivity theory (CRT) so as to give it a deep foundation in density-functional theory (DFT), Parr, his collaborators, and subsequent workers have introduced reactivity indices as properties of isolated reactants, some of which are in apparent conflict with the underlying DFT. Indices which are first derivatives with respect to electron number are staircase functions of number, making electronegativity equalization problematic. Second derivative indices such as hardness vanish, putting hardness-based principles out of reach. By reformulating CRT within our partition theory, which provides an exact decomposition of a system into its component species, we resolve the conflict. We show that the reactivity of a species depends on its chemical context and define that context. We establish when electronegativity equalization holds and when it fails. We define a generalization of hardness, a hardness matrix containing the self-hardness of the individual species and the mutual hardnesses of the pairs of species of the system, and identify the physical origin of hardness. We introduce a corresponding generalization of the Fukui function as well as of the local and global softnesses and the softness kernel of the earlier formulation. We augment our previous formulation of the partition theory by introducing a model energy function and express the difference between the exact and the model forces on the nuclei in terms of the new reactivity indices. For simplicity, our presentation is limited to time-reversal invariant systems with vanishing spin density; it is straightforward to generalize the theory to finite spin density.
机译：在制定化学反应性理论（CRT）以便为密度泛函理论（DFT）奠定深厚的基础时，Parr，他的合作者和随后的工作人员引入了反应性指数作为分离的反应物的性质，其中有些显然是与基础DFT发生冲突。关于电子数的一阶导数的指数是数的阶梯函数，使得电负性均衡成为问题。二阶导数指数（例如硬度）消失了，这使基于硬度的原理无法实现。通过在分区理论内重新构造CRT（可将系统准确分解为系统的组成部分），我们解决了冲突。我们证明了物种的反应性取决于其化学背景，并定义了该背景。我们确定电负性均衡何时成立以及何时失败。我们定义硬度的一般化，包含单个物种的自身硬度和系统中成对物种的相互硬度的硬度矩阵，并确定硬度的物理来源。我们介绍了对Fukui函数以及本地和全局软度以及较早公式的软核的相应概括。我们通过引入模型能量函数来扩充我们先前对分配理论的表述，并根据新的反应性指数表达精确作用力与模型作用力之间的差异。为简单起见，我们的介绍仅限于自旋密度消失的时间反向不变系统。将理论推广到有限的自旋密度是很简单的。

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