Ab initio study of cationic water cluster (H2O)9+ via particle swarm optimization algorithm

Publication date: 15 November 2017 Source:Computational and Theoretical Chemistry, Volume 1120 Author(s): Lan-Ting Shi, Mei Tang, Xiang-Rong Chen, Cui-E Hu, Yan Cheng The 16 lowest energy isomers of cationic water cluster (H2O)9 + have been comprehensively searched by the particle swarm optimization algorithm combined with quantum chemistry calculations. Geometric optimization and vibration analysis of the interesting isomers were made in the MP2/aug-cc-pVDZ level. Our results show that cage structure is the most stable at low temperatures. The relative Gibbs free energy below 400K was calculated, which indicates that the stability of the cage structure decreases as the temperature increases while the energy of ring is relatively slow. We also illustrate the computationally simulated IR spectra obtained at six different calculated levels and individual IR spectroscopy for seven isomers. The obtained molecular orbits of six representative isomers show good agreement with experiment. Finally, through the topological analysis and density gradient analysis, we compared the interaction between the H3O+ core and H2O as well as the OH radicals. Graphical abstract

Source: Computational and Theoretical Chemistry - October 20, 2017 Category: Chemistry Source Type: research