Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 55: Theoretical methods II
O 55.3: Vortrag
Mittwoch, 28. März 2012, 17:15–17:30, MA 043
Ferrocene-Peptide Charge Transfer on Gold Surface: a First Principles Study — •Filipe C. D. A. Lima1, Arrigo Calzolari2, and Helena M. Petrilli1 — 1Universidade de São Paulo, Instituto de Física - Brasil — 2CNR-NANO Istituto Nanoscienze, Centro S3- Italia
Ferrocene-peptide self-assembled layers are one of the most studied redox-active assemblies on metal surfaces as prototypical models to probe heterogeneous electron transfer at hybrid interfaces. Recent experimental investigations have shown that the electron transfer in peptides can occur across long distances, by separating the donor from the acceptor.From the experimental point of view, it is not clear which charge transfer mechanism occurs in this type of system. We study the interaction of an oligo-peptide chain Fc-Gly-CSA (Ferrocene, Glycine and Cystamine) on the Au(111) from first principles calculations to evaluate its electron transfer mechanism. The method employed is based on the KS-DFT as implemented in the Quantum-ESPRESSO suit of codes, using ultrasoft pseudopotentials and the GGA-PBE exchange correlation functional to evaluate the ground-state atomic and electronic structure of the system. By analyzing the KS orbital at the Fermi Energy we see a high electronic density at the Ferrocene and minor contributions from the solvent and counter ion. On the other hand, higher energy states mainly contributes to the gold surface. We infer the considered models are able to simulate heterogeneous electron transfer and the results indicates an electron tunneling mechanism from the Ferrocene to the Surface.