Molecular Simulation and Modeling of Water and Aqueous Solutions in Bulk and at Interfaces: From Ambient to Supercritical Conditions

In this talk, we review our simulation and theoretical research on water and aqueous solutions, both in bulk and at interfaces (particularly metal oxide interfaces), and at conditions ranging from ambient to supercritical. One research focus has been the development of intermolecular potentials for water. We have had as our goal the development of a polarizable model for water whose bare dipole moment matches that of the isolated water molecule (1.85D), that accurately predicts the structure of water at ambient and supercritical conditions, and that reproduces thermodynamic and dielectric behavior, including the phase envelope. We will describe the evolution of our model from its earliest forms [1] to the latest [2], which achieves many of the goals we set for our model.

Secondly, we describe our simulations of water and electrolyte species at metal oxide interfaces. Using a combination of ab initio calculations and classical molecular dynamics we have predicted the disstribution of various ionic species as a function of distance from the 110 surface of rutile, and the sites at which the ions adsorb into the surface. These predictions are compared with x-ray standing wave (XRSW) measure ments and found to be in remarkably good agreement [3].

References

1. A. A. Chialvo and P. T. Cummings, J. Chem. Phys., 1996, 105, 8274-8281; A. A. Chialvo and P. T. Cummings, Fluid Phase Equilibria, 1998, 150-151, 73-81.

2. Paricaud, P., et al., J. Chem. Phys., 2005, 122, Art. No. 244511; Dyer, P. J. and Cummings, P. T., J. Chem. Phys., 2006, 125, Art. No. 144519.

3. Z. Zhang et al., Langmuir, 2004, 20, 4954-4969; M. Predota, et al., J. Phys. Chem. B, 2004, 108, 12049-12060; ibid, 2004, 108, 12061-12072; Predota, M., et al., J. Phys. Chem. C, 2007, 111, 3071-3079; Mamontov, E., et al., J. Phys. Chem. C, 2007, 111, 4328-4341.