IDENTIFICATION OF 2 DISTINCT STRUCTURAL AND DYNAMIC DOMAINS IN AN AMORPHOUS WATER CLUSTER

This investigation is focused on dynamics and structure of an amorphous water cluster (H2O)116. The cluster was obtained in a previous study by simulation of the condensation of amorphous ice. The time evolution of the cluster is studied on a ∼400 ps time scale, using the classical trajectory technique at different temperatures. Two distinct structural and dynamical domains are identified. At 36 K the cluster displays glass-like behavior. There is also a broad distribution of molecular states extending from 1- to 5-coordinated water molecules. Upon heating to 100 K the cluster undergoes a transition to a more compact structure. The molecular energy distribution narrows down and is dominated by 3- and 4-coordinated molecules. After the transition the cluster displays liquid-like characteristics. All these changes are not reflected by the normal frequency distribution of structures along the trajectory. © 1990 American Institute of Physics.