Simulations of vapor water clusters at vapor–liquid equilibrium

Abstract

The Gibbs-ensemble Monte Carlo methods based on the extended single point charge [H. J. C. Berendsen, J. R. Grigera, and T. P. Straatsma, J. Phys. Chem. 91, 6269 (1987)] potential-energy surface have been used to study the clustering of vapor phase water under vapor-liquid equilibrium conditions between 300 and 600 K. It is seen that the number of clusters, as well as the cluster size, increase with temperature. This is primarily due to the increase in vapor density that accompanies the temperature increase at equilibrium. In addition, due to entropic effects, the percentage of clusters that have linear (or open) topologies increases with temperature and dominates over the minimum-energy cyclic topologies at the temperatures studied here. These results are insensitive to the number of molecules used in the simulations and the criterion used to define a water cluster.

Collisional cross-section of water molecules in vapour studied by means of 1H relaxation in NMR

“…Under our experimental conditions, water vapour is mainly monomeric505152 and the extreme narrowing regime is not fulfilled: R 1 shows a maximum at a pressure p max where τ J  = 1/(ω O  − ω J ) (see Fig. 1).…”

Effect of the local hydrogen bonding network on the reorientational and translational dynamics in supercritical water

“…Therefore, our choice has been based on previously reported simulation results concerning the accuracy of this model in reproducing reasonably various properties of the fluid. [42][43][44][45] In our simulations a cutoff radius of 12.0 Å has been applied for Lennard-Jones interactions and long-range corrections have been also taken into account. Moreover, to account for the long-range electrostatic interactions the Ewald summation technique was used based on the more exact approximation of the Newton-Gregory forward difference interpolation scheme.…”

Solvation processes in steam: Ab initio calculations of ion–solvent structures and clustering equilibria

“…(10). These results are of interest given the recent findings by Mhin et al (1993), Johansson et al (2005), Benjamin et al (2006) and Slanina et al (2006) who demonstrated that for neutral-water clusters (H 2 O) m at vapor saturation, there are more smaller than larger clusters at any given temperature from 300 to 646 K. We assume that this reversal in cluster abundance is due to the more endergonic binding of water in (H 2 O) m than the corresponding water attachment in the ion cluster H 3 O + Á(H 2 O) m . Note that for m = 1, binding energies for the above clusters obtained from experiment are 10.5 kJ mol À1 (Curtiss et al, 1979) and À102.2 kJ mol À1 (Likholyot et al, 2007), respectively.…”