An accurate analytic representation of the water pair potential†
Abstract
The ab initiowater dimer interaction energies obtained from coupled cluster calculations and used in the CC-pol water pair potential (Bukowski et al., Science, 2007, 315, 1249) have been refitted to a site–site form containing eight symmetry-independent sites in each monomer and denoted as CC-pol-8s. Initially, the site–site functions were assumed in a B-spline form, which allowed a precise optimization of the positions of the sites. Next, these functions were assumed in the standard exponential plus inverse powers form. The root mean square error of the CC-pol-8s fit with respect to the 2510 ab initio points is 0.10 kcal mol−1, compared to 0.42 kcal mol−1 of the CC-pol fit (0.010 kcal mol−1 compared to 0.089 kcal mol−1 for points with negative interaction energies). The energies of the stationary points in the CC-pol-8s potential are considerably more accurate than in the case of CC-pol. The
- This article is part of the themed collection: Water at interfaces