Growth and structure of amorphous ice condensates: A computational study. II

Investigation is presented of the static and the dynamic properties of an amorphous cluster (H2O)450 at T≊10 K. The cluster was obtained in a simulation of slow condensation of gaseous water molecules, and is used here to obtain insights into molecular properties of low temperature amorphous ice deposits. The cluster is shown to contain a substantial fraction of molecules of hydrogen bond coordination less than 4. Low coordinated configurations are formed during condensation in a highly selective fashion, i.e., some configurations are strongly favored over others. Condensation dynamics is investigated, in an effort to clarify a link between molecular mechanisms of condensation and the resulting metastable structure. Physical reason is suggested for the experimentally measured very large surface area of the amorphous ice deposits.