IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
artículos
Título:
Experimental and theoretical studies of L-cysteine adsorbed on Ag(111) electrodes
Autor/es:
E. SANTOS, L.B. AVALLE, K. P¨OTTING, P. V´ELEZ, H. JONES
Revista:
ELECTROCHIMICA ACTA
Editorial:
Elsevier
Referencias:
Año: 2008 vol. 53 p. 6807 - 6817
ISSN:
0013-4686
Resumen:
We have investigated L-cysteine adsorbed on Ag(111) electrodes under different conditions.We have employed experimental and theoretical approaches to obtain a better understandingof the adsorbed layer. An estimation of the coverage from charge measurements and thesecond harmonic response shows C3v symmetry for the interface indicating a (√3x√3)R°30overlayer. The theoretical calculations show a variety of different structures with localadsorption energy minima. Particularly, under special initial conditions, zwitterionicstructures adsorbed at different sites have been found. This can account for the multiplicity ofredox processes observed experimentally below the potential of zero charge. The presence ofan external field produces the stabilization of the zwitterion by interaction of the amino /carboxylic groups with the substrate.