Simulation of supercritical water and of supercritical aqueous solutions

Abstract

Articles you may be interested inStatic and dynamic structural analysis of a saturated solution of ZnBr2 in water: Anomalous xray diffraction and molecular dynamics simulations Molecular dynamics simulation of water beween two ideal classical metal walls Molecular dynamics (MD) calculations have been performed to determine equilibrium structure and properties of systems modeling supercritical (SC) water and SC aqueous solutions at two states near the critical point using the simple point charge (SPC) potential model of Berendsen et al. for water. Both thermodynamic and dielectric properties from the simulations for pure water are accurate in comparison with experimental results even though the SPC model parameters were fitted to properties of ambient water. Details of the nearcritical clustering in SC water have been predicted which have not been measured to date. MD studies have also been undertaken of systems that model sodium and chloride ions and neutral argon in SC water at the same states. The first solvation shell in SC water is observed to be similar to that in ambient water, and long-range solvation structures in SC water are similar to those observed for simple SC solvents. An excess of water molecules is observed clustering around ionic solutes which behave attractively and a deficit is observed around neutral atomic solutes which behave repulsively. These results should be helpful in developing a qualitative understanding of important processes that occur in SC water. 5606

Solvation in supercritical water

“…Some of the results presented herein were obtained from the same simulations as described previously in Cummings et al (1991); specifically, the pair correlation functions presented here in Figs. 1 and 2 (except for methanol) and the integrals of pair correlation functions presented here in Figs.…”

“…Calculations of the thermodynamic and dielectric properties of pure SC water at T, = T/T, = 1.00 and pr = p/p, = 1.50, the dense SC state, and at T, = 1.05 and pr = 1.00, the near-critical SC state, (Cummings et al, 1991) demonstrated the remarkable accuracy of the SPC model even for SC states.…”

“…Calculations were performed by the molecular dynamics technique in the canonical, isokinetic ensemble using a fourth order Gear predictor-corrector algorithm. The details have been presented by Cummings et al (1991). Water interactions were modeled by the simple point charge (SPC) model of Berendsen et al (1981) which consists of a spherical Lennard-Jones (LJ) potential centered on the oxygen atom with partial point charges located so as to result in good prediction of the properties and structure of ambient water.…”

Molecular Simulations of Dense Hydrothermal NaCl−H2O Solutions from Subcritical to Supercritical Conditions

“…16 Expanding the investigation to finite concentrations, Cummings and co-workers examined the structure of SPC water solutions at supercritical conditions and established a baseline of qualitative results for supercritical solution structure. 17 Hummer and collaborators examined a 21 wt % dense NaCl brine at a single temperature and fixed density 18 as part of a comparison of RISM, Monte Carlo (MC), and MD methods in the development of a new reaction-field formulation. 19 A similar, more concentrated system at 28 wt % was simulated by Rode, 20 from gaseous to liquid densities at subcritical temperatures, giving a first look at ion association in low-density systems and the overall effect on solution structure.…”

Effective Pair Potentials and Structure of Water

“…The aim of this work was to investigate the performance of the TIP4P, the SPC, and the SPCE models to reproduce the structure of liquid water at various thermodynamic conditions. Several papers have been published in which the pair correlation functions of water obtained by simulation have been compared with experimental results [19][20][21][22][23][24][25][26]28]. The three models represent very well the water 0-0 pair correlation function at various T-p conditions, observing that in general the first peak is too high when compared with the experimental one.…”