[gmx-users] dissociative water models

[Mark Abraham]

There's been some discussion lately on dissociative water models, and I 
saw this paper http://dx.doi.org/10.1021/jp072530o, which may be of 
interest to some people.

Dissociative Water Potential for Molecular Dynamics Simulations
T. S. Mahadevan and S. H. Garofalini*
J. Phys. Chem. B; 2007; ASAP Web Release Date: 30-Jun-2007

A new interatomic potential for dissociative water was developed for use 
in molecular dynamics simulations. The simulations use a multibody 
potential, with both pair and three-body terms, and the Wolf summation 
method for the long-range Coulomb interactions. A major feature in the 
potential is the change in the short-range O-H repulsive interaction as 
a function of temperature and/or pressure in order to reproduce the 
density-temperature curve between 273 K and 373 at 1 atm, as well as 
high-pressure data at various temperatures. Using only the change in 
this one parameter, the simulations also reproduce room-temperature 
properties of water, such as the structure, cohesive energy, diffusion 
constant, and vibrational spectrum, as well as the liquid-vapor 
coexistence curve. Although the water molecules could dissociate, no 
dissociation is observed at room temperature. However, behavior of the 
hydronium ion was studied by introduction of an extra H+ into a cluster 
of water molecules. Both Eigen and Zundel configurations, as well as 
more complex configurations, are observed in the migration of the hydronium.