SUBSTRATE-INDUCED STRAIN OF UPD MONOLAYERS AND 2-DIMENSIONAL 3-DIMENSIONAL TRANSITION IN METAL ELECTRODEPOSITION

Various reasons for the appearance of substrate-induced strain in unde rpotential deposition (UPD) monolayers on strongly attractive substrat es are discussed. An expression for the dependence of monolayer compre ssion on underpotential is obtained considering the two-dimensional fi lm as isotropic and elastic. A theoretical model is proposed for the n ucleation of the three-dimensional metal bulk phase taking into accoun t the compressive strain of the UPD monolayer. It is shown that previo us results from electrochemical measurements for lead deposition on Ag (111) as well as recent experimental data obtained by in-situ X-ray sc attering and scanning tunnelling microscopy are in good agreement with the theoretical considerations.