Mechanistic analysis of electron transfer at film–modified metal electrodes and computation of associated electronic structure and energtics

PHYS 122

Marshall D. Newton, Newton@bnl.gov, Chemistry Department, Brookhaven National Laboratory, Bldg. 555A, Upton, NY 11973-5000
Theoretical and computational techniques are used to elucidate the physical and chemical factors that control the kinetics of interfacial electron-transfer (ET) reactions, including those for which standard rate constants (k0(l)) have been measured electrochemically for ET between substrate Au electrodes and redox couples attached to the electrode surfaces by variable lengths (l) of oligomethylene (OM), oligophenylenevinylene (OPV) and oligophenyleneethynylene (OPE) bridges. These oligomers are components of mixed self-assembled monolayers (SAMs), coupled to the substrate via S atom linkers. The mechanistic analysis of the kinetic behavior is supported by calculations of electronic structure and molecular and medium energetics. Band structure calculations for neat phenylthiolate SAMs on Au and Cu susbstrates were used to probe the properties of the interface, including surface dipole layer and work function and the electronic nature of the ‘thiolate' linker atoms.

This research was supported by the Division of Chemical Sciences, U.S. Department of Energy, under grant DE-AC02-98CH10886.