Size and topology of molecular clusters in supercritical water: a molecular dynamics simulation

A hybrid criterion of hydrogen bonding is applied to the analysis of molecu lar dynamics trajectories simulated for several near- and supercritical the rmodynamic conditions. Even at vapor-like densities supercritical water is shown to contain large molecular clusters, consisting of up to 10 molecules . Relative abundances of topologically different trimers, tetramers, and pe ntamers are examined, and chain-like clusters are found predominant under s upercritical conditions. In contrast to the results of quantum-chemical cal culations for isolated water clusters, ring-like clusters are only rarely f ormed in supercritical water. (C) 1999 Elsevier Science B.V. All rights res erved.