title: p-Nitrobenzoic acid adsorption on nanostructured gold surfaces investigated by combined experimental and computational approaches.
abstract: Adsorption of guest molecules on host surfaces can lead to dramatic changes in the spectral properties of the guest. One such effect is surface-enhanced infrared absorption (SEIRA), observed when the guest is adsorbed on, for example, thin films, metal surfaces, or nanotubes. p-Nitrobenzoic acid (p-NBA) exhibits a SEIRA effect when adsorbed on Ag and Au. Herein, the IR spectra of p-NBA adsorbed on a homemade rough Au surface, recorded in reflection mode with an angle of incidence of 16.5°, are reported. This SEIRA experiment reveals more bands than found by previous SEIRA studies. The intensities of both symmetric and asymmetric COO(-) and NO(2) stretching, in-plane CH, and C=C ring stretching modes are enhanced. Theoretical models constructed on the basis of density functional theory reveal the binding mode of p-NBA to gold "particles". The p-NBA anion binds to gold much more strongly than the neutral form, and interaction via the carboxylic oxygen atoms is preferred over the nitro group-gold contact. A significant charge transfer during chemisorption is found, which is considered to be crucial in leading to a high SEIRA enhancement factor.
authors.affiliation: Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland. jarek@elrond.chem.uni.wroc.pl
authors.forename: Jarosław J
authors.initials: JJ
authors.lastname: Panek
authors.forename: Aneta
authors.initials: A
authors.lastname: Jezierska-Mazzarello
authors.forename: Aleksander
authors.initials: A
authors.lastname: Koll
authors.forename: Galina
authors.initials: G
authors.lastname: Dovbeshko
authors.forename: Olena
authors.initials: O
authors.lastname: Fesenko