Liu Yiliang, Hua Yawen, Yan Anying, Wu Shuang, Chen Jun
College of Electrical and Information Engineering and Key Laboratory of Information Materials of Sichuan Provincial Universities, Southwest Minzu Nationalities, Chengdu, 610041, People's Republic of China.
Science and Technology on Surface Physics and Chemistry Laboratory, Mianyang, 621907, People's Republic of China.
J Mol Model. 2019 Jul 9;25(8):214. doi: 10.1007/s00894-019-4099-z.
Al clusters exhibit apparent changes in curvature, which resemble macroscopic metal tips. Here, we show, using the density functional theory method, how surface charges of Al (q = -2 to +3) ions affect the adsorption and dissociation behavior of HCl molecules. Geometries, adsorption energies, vibrational frequencies, Mulliken population analysis and transition states of (AlHCl) (q = -2 to +3) adsorption complexes were studied. The results revealed that HCl molecules tend to locate on tip sites of the Al (q = -2 to +3) ions. Anionic adsorption complexes are prone to H affinity adsorption, whereas cationic adsorption complexes favor Cl-affinity adsorptions. These adsorption behaviors look quite like macroscopic tip effects. H-Cl bonds of the adsorption complexes weaken with an increase in either positive or negative charge. Dissociation barriers of the H-Cl bonds exhibit binding energies that are 2 orders of magnitude smaller than those of an isolated HCl molecule. Considering adsorption energies and dissociation barriers comprehensively, HCl molecules should dissociate spontaneously for all the models considered. Generally, the more negative charges the clusters carry, the more energy the reaction will release. Graphical abstract Dissociation barriers of the H-Cl bonds in Al (q = -2 - +3) cluster ions exhibit energy barriers ~2 orders of magnitude smaller than isolated HCI molecules.
铝簇在曲率上呈现出明显变化，类似于宏观金属尖端。在此，我们使用密度泛函理论方法展示了铝（q = -2至+3）离子的表面电荷如何影响HCl分子的吸附和解离行为。研究了（AlHCl）（q = -2至+3）吸附络合物的几何结构、吸附能、振动频率、 Mulliken布居分析和过渡态。结果表明，HCl分子倾向于位于铝（q = -2至+3）离子的尖端位置。阴离子吸附络合物易于发生氢亲和吸附，而阳离子吸附络合物则有利于氯亲和吸附。这些吸附行为很像宏观尖端效应。吸附络合物的H-Cl键随着正电荷或负电荷的增加而减弱。H-Cl键的解离势垒所表现出的结合能比孤立HCl分子的结合能小2个数量级。综合考虑吸附能和解离势垒，对于所有考虑的模型，HCl分子都应自发解离。一般来说，簇所带的负电荷越多，反应释放的能量就越多。图形摘要：铝（q = -2 - +3）簇离子中H-Cl键的解离势垒所呈现的能垒比孤立HCl分子小约2个数量级。
