Structure and stability of galena (PbS) at the interface with aqueous solution: a combined embedded cluster/reaction field study

We have explored the adsorption and reactivity of molecular water on the su rface of PbS (galena) and its interface with aqueous solution, employing th e recently proposed CECILIA method [E.V. Stefanovich, T.N. Truong, J. Chem. Phys. 106 (1997) 7700]. Using an embedded cluster model of the solid and i ncluding the effects of bulk water via a reaction field, our results sugges t that physisorption occurs at the perfect (001) surface, with a barrier to molecular adsorption at around 5 Angstrom above the surface. At a step def ect, chemisorption of the water is found. The barrier to dissociation is in creased upon inclusion of the effect of aqueous solution. Reasons for these findings are discussed. (C) 2000 Elsevier Science B.V. All rights reserved .