An ab initio study of water clusters in gas phase and bulk aqueous media: (H2O)n, n=1–12

摘要: Geometries of several clusters water molecules including single minimum energy structures n-mers (n=1–5), hexamers and two each heptamer to decamer derived from hexamer cage prism were optimized. One structural form 11-mer 12-mer also studied. The geometry optimization calculations performed at the RHF/6-311G* level for all cases MP2/6-311++G** some selected cases. optimized cluster geometries used calculate total energies in gas phase employing B3LYP density functional method 6-311G* basis set. Frequency analysis was carried out ensure that corresponded minima. Zero-point thermal free corrections applied comparison certain hexamers. solvate bulk using polarized continuum model (PCM) self-consistent reaction field (SCRF) theory, set, method. For which performed, solvation method, 6-311++G** PCM SCRF besides corresponding gas-phase calculations. It is found most stable among different hexamers, agreement with earlier theoretical experimental results. Further, use a newly defined relative population index (RPI) terms successive differences per molecule sizes suggests stabilities trimers, nonamers those would be favored while pentamer both phases relatively disfavored. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 81: 90–104,