The adsorption of the cysteine amino acid (H-SCbetaH2-CalphaH-NH2-COOH) on the (111) surface of gold is studied by means of periodic density functional calculations. Results for different adsorption sites and molecular configurations show that chemisorption involving S(thiolate)-Au bonds on Au(111) is favored by starting with either cysteine or cystine gas-phase molecular precursors. In the most stable adsorption configuration, the sulfur headgroup sits at the bridge site between two surface An atoms, and the S-C-beta bond is tilted by 57degrees with respect to the surface normal, whereas the in-plane orientation of the molecular backbone plays a secondary role. The analysis of the electronic properties shows that the hybridization of the p-like S states with the d-like Au states produces both bonding and antibonding occupied orbitals, and the process is well described by a model for the interaction of localized orbitals with narrow-band dispersive electron states. The bonding orbitals well below the Fermi level contribute to the strong chemisorption of cysteine on gold. The calculated sulfur-projected density of states allows us to locate the cysteine molecular orbitals with respect to the system Fermi level, which gives a measure of the injection barrier at the molecule/electrode junction.

A DFT Study of Cysteine Adsorption on Au(111) / DI FELICE, Rosa; A., Selloni; Molinari, Elisa. - In: JOURNAL OF PHYSICAL CHEMISTRY. B, CONDENSED MATTER, MATERIALS, SURFACES, INTERFACES & BIOPHYSICAL. - ISSN 1520-6106. - STAMPA. - 107:5(2003), pp. 1151-1156. [10.1021/jp0272421]

A DFT Study of Cysteine Adsorption on Au(111)

DI FELICE, ROSA;MOLINARI, Elisa
2003

Abstract

The adsorption of the cysteine amino acid (H-SCbetaH2-CalphaH-NH2-COOH) on the (111) surface of gold is studied by means of periodic density functional calculations. Results for different adsorption sites and molecular configurations show that chemisorption involving S(thiolate)-Au bonds on Au(111) is favored by starting with either cysteine or cystine gas-phase molecular precursors. In the most stable adsorption configuration, the sulfur headgroup sits at the bridge site between two surface An atoms, and the S-C-beta bond is tilted by 57degrees with respect to the surface normal, whereas the in-plane orientation of the molecular backbone plays a secondary role. The analysis of the electronic properties shows that the hybridization of the p-like S states with the d-like Au states produces both bonding and antibonding occupied orbitals, and the process is well described by a model for the interaction of localized orbitals with narrow-band dispersive electron states. The bonding orbitals well below the Fermi level contribute to the strong chemisorption of cysteine on gold. The calculated sulfur-projected density of states allows us to locate the cysteine molecular orbitals with respect to the system Fermi level, which gives a measure of the injection barrier at the molecule/electrode junction.
2003
107
5
1151
1156
A DFT Study of Cysteine Adsorption on Au(111) / DI FELICE, Rosa; A., Selloni; Molinari, Elisa. - In: JOURNAL OF PHYSICAL CHEMISTRY. B, CONDENSED MATTER, MATERIALS, SURFACES, INTERFACES & BIOPHYSICAL. - ISSN 1520-6106. - STAMPA. - 107:5(2003), pp. 1151-1156. [10.1021/jp0272421]
DI FELICE, Rosa; A., Selloni; Molinari, Elisa
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/20592
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