Penotti Fabio E, Cooper David L, Karadakov Peter B
Consiglio Nazionale delle Ricerche Istituto di Scienze e Tecnologie Chimiche "Giulio Natta", Via Golgi 19, I-20133 Milano, MI, Italy.
Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, U.K.
J Phys Chem A. 2021 May 13;125(18):3912-3919. doi: 10.1021/acs.jpca.1c02422. Epub 2021 May 4.
The most important factor behind the intriguing differences between the geometries of the M'AlH (M' = Mg, Ca) molecules is shown to be dynamical electron correlation and not intramolecular Coulombic interactions, as previously thought. Spin-coupled generalized valence bond (SCGVB) calculations reveal the different bonding situations in the two molecules at their optimal geometries but do not explain why these geometries differ so much; the solution to this conundrum comes instead from detailed analysis of coupled-cluster (CCSD(T)) energies at model and optimal geometries.
事实证明，M'AlH（M' = Mg、Ca）分子几何结构之间存在有趣差异的背后，最重要的因素是动态电子关联，而非如之前所认为的分子内库仑相互作用。自旋耦合广义价键（SCGVB）计算揭示了这两种分子在其最佳几何结构下不同的键合情况，但并未解释为何这些几何结构差异如此之大；这个难题的解决方案反而来自于对模型几何结构和最佳几何结构下耦合簇（CCSD(T)）能量的详细分析。
