Computer simulation of dissociative adsorption of water on CaO and MgO surfaces and the relation to dissolution

Atomistic simulation techniques have been employed to model the dissociative adsorption of water at three-, four- and five-coordinated surface sites of CaO and MgO crystals in a series of partial coverages. Ail sites can be hydroxylated but the lower-coordinated sites are found to be more reactive. The calculated hydration energies agree with experiment where available. Investigating dissolution of cation-oxygen pairs from various surface sites shows the process to be energetically possible on all surfaces but more exothermic at the lower-coordinated sites.