A density functional water dimer potential surface

Abstract

A full six-dimensional intermolecular potential surface for the water dimer is obtained using density functional theory. The surface was evaluated at 20 480 numerical quadrature points using a hybrid functional. It was then fitted to products of rotational functions. The equilibrium geometry and the transition states on the surface were located and their features are in agreement with previous ab initio studies. The binding energy and the barrier heights are slightly underestimated. We believe that the surface faithfully represents many of the important features of the water dimer potential.