Rational development of nanotechnology through electrochemistry requires a thorough understanding of electronic magnetic as well as atomic level structural details of surfaces under electrochemical environments Using first principles density functional theory (DFT) we investigated these features in the mechanism of metallizing a self-assembled monolayer of organic molecules attached to a metallic surface with Pd We focused our studies on the root 3 x root 3 structure of the 4-mercaptopyridine (4MP)-SAM adsorbed on Au(1 1 1) first elucidating the nature of metal-SAM interactions and then providing a general mechanism to explain the initial stages of SAM-metallization with Pd Calculations support that SAM relaxation permits facile aggregation of metal atoms to form a hanging metal overlayer The calculated electronic structures of possible overlayers interacting with the supporting SAM are compared to experiment (C) 2010 Elsevier Ltd All rights reserved