Vapor-liquid equilibria of water from first principles: comparison of density functionals and basis sets

• Published in: Molecular physics 2006-11, Vol.104 (22-24), p.3619-3626
• Main Authors: McGrath, M. J., Siepmann, J. I., Kuo, I.-F. W., Mundy, C. J.
• Format: Article
• Language: English
• Subjects: Density functional theory; Monte Carlo; Phase equilibria; Water
• ISSN: 0026-8976; 1362-3028
• DOI: 10.1080/00268970601014781

Gibbs ensemble Monte Carlo simulations were run with an efficient mixed-basis electronic structure method to explore the phase equilibria of water from first principles using Kohn-Sham density functional theory. The Perdew-Burke-Ernzerhof exchange/correlation density functional gives a higher critical temperature (700 K) and boiling point (480 K) than experiment, although good agreement is found for the saturated liquid densities. A systematic increase in the size of the basis set for the Becke-Lee-Yang-Parr exchange/correlation density functional from a double-ζ to quadruple-ζ split valence leads to further deviations from experiment on the saturated liquid and vapor densities, while the intermediate basis set gives the best results for the heat of vaporization at T = 423 K. Analysis of the liquid structure for all simulations shows changes that can partially be explained by the different densities at a given temperature, and both density functionals show a similar temperature dependence of the liquid structure.