Structural exploration and properties of (H2O)4+ cluster via ab initio in combination with particle swarm optimization method

• Published in: Chemical physics Vol. 452; pp. 25 - 30
• Main Authors: Lv, Zhen-Long, Cheng, Yan, Chen, Xiang-Rong, Cai, Ling-Cang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2015
• Subjects: Ab initio calculation; Cationic water cluster; Gibbs free energy; Singly occupied orbital; Vibrational analysis; Ab initio calculation; Gibbs free energy; Vibrational analysis; Cationic water cluster; Singly occupied orbital
• ISSN: 0301-0104
• DOI: 10.1016/j.chemphys.2015.02.016

[Display omitted] •Particle swarm optimization method was used to search isomers of (H2O)4+ cluster.•Eighteen lower energy isomers of three types were obtained at the MP2 level.•Relationship between isomers’ structures and their energy ordering was analyzed.•Simulated infrared spectra of the lower energy isomers were experimentally verified.•Characteristics of the HOMO and LUMO of these three types of isomers were revealed. As a microscopic model to study ionized water, cationic water clusters are hot research subjects in these days, which also has many unique properties compared with their neutral counterparts. Here, the isomers of (H2O)4+ cluster were searched by using particle swarm optimization method with the help of quantum chemical calculations. Eighteen stable candidates were obtained after optimization performed at the MP2/aug-cc-pVDZ level. Their relative Gibbs free energies below 350K, the infrared spectra of the five lowest energy isomers and the electronic characteristics of the representative isomers were investigated. For these isomers, the effect of the zero point vibrational energies, the relationship between the schemes of the isomers and their energies, and the constituents of the most important orbitals were studied, which provide us with much information for further studying this kind of clusters.