title: Application of the independent molecule model to the calculation of free energy and rigid-body motions of water heptamers and octamers.
abstract: Stabilization of clusters of water heptamer and octamer in the gas phase is studied with the independent molecule model. As indicators of stabilization, the H-bonding strength, the H-bonding lifetime and the free energy are calculated. For both the heptamers and octamers, clusters with one oxygen-ring and some branching H-bonded waters are more stable than clusters with multi-oxygen-rings. Both the heptamer and octamer prefer a shape intermediate between planar and polyhedral; the branched waters are highly fluctuating and consequently contribute to increasing the entropy of the cluster. As the temperature increases from 0 to 300 K, the entropy contributes to the differentiation in free energy of the cluster geometries.
authors.affiliation: Yatsushiro National College of Technology, Yatsushiro 866-8501, Japan. yoshioki@as.yatsushiro-nct.ac.jp
authors.forename: Shuzo
authors.initials: S
authors.lastname: Yoshioki
mesh_terms: D005740:Gases; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008968:Molecular Conformation; D009038:Motion; D013696:Temperature; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D005740:Gases; D014867:Water