RELAXATIONS, FLUCTUATIONS, PHASE-TRANSITIONS AND CHEMICAL-REACTIONS IN LIQUID WATER

Fluctuations and collective motions in liquid water and their effects on chemical reactions dynamics are analyzed. Liquid water is a 'frustrated' system with multiple random hydrogen bond network structures, and has anomalous microscopic and macroscopic properties. Rearrangement dynamics of the hydrogen bond network induces collective motions of water molecules and energy fluctuations. Vibrational motions of photoexcited molecules strongly resonate to these water fluctuations, and thus energy dissipation processes in liquid water are extremely fast. Time scale, spatial scale and energy scale of the collective motions are analyzed by examining potential energy surfaces involved. A model of hydrogen bond network based on the functional integral method is presented and spatial and energy scales of fluctuations are discussed. Instability of hydrogen bond network is studied to understand the physical origin of these microscopic and macroscopic anomalies of liquid water.