Structures of adsorbed water layers on MgO: an ab initio study

A systematic search using an ab initio density-functional method has been carried out for energy minima for a monolayer of water on MgO. Minima were sought in which one third of the water molecules were dissociated, and the observed p(3 x 2) symmetry satisfied. Six such minima were found, three of which are within 300k(B) per water molecule of the lowest energy structure. We also found a structure with a similar energy with (2 x 2) symmetry and half the water molecules dissociated. The structures are stabilised by the donation of three hydrogen bonds to each hydroxide ion. (C) 2001 Elsevier Science B.V. All rights reserved