Relative Distribution of Water Clusters at Temperature (300-3000K) and Pressure (1-500MPa)

At 300-3000K and 1-500MPa, variations of relative contents for small water clusters (H2O)n (n=1~6) were calculated by using statistical mechanical methods. First, 9 kinds of small water clusters were selected and their structures were optimized by using ab initio method. In the wide range of temperature (300-3000K) and pressure (1-500MPa), their equilibrium constants of reactions for formation of 9 kinds of water clusters were determined by using molecular partition function. Next, changes of contents (molar fractions) as function of temperature and pressure were estimated. The obtained results for small water clusters can be used to interpret temperature-pressure dependency of the average number for the hydrogen bonds in water clusters and redistribution of the water clusters at the ultrasonic cavitation reactions.