Quantum-Chemical Study of the Adsorption of Pb 2+ on Au(111)

The interaction between the Pb2+ ion and gold is studied using the cluster metal surface model and the density functional method. The geometric and energy characteristics of the interaction between this ion and the gold surface are estimated. The form in which the Pb2+ ion exists on the surface is more ad-ionic than ad-atomic. The electron structure of the Au–Pbads2+ system is analyzed. The participation of the adsorbed lead ion and its neighboring gold atoms in the formation of molecular orbitals in this system is estimated. It is established that the contribution to their formation is predominantly provided by the lead s-orbitals and the gold d-orbitals. The interaction with a solvent decreases the transfer of a charge from an adsorbed lead ion to gold. It is demonstrated that the hydrolyzability of a lead ion decreases upon its transition from the electrolyte phase to the surface.