IFISUR   23398
INSTITUTO DE FISICA DEL SUR
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Adsorption of dopamine species on Ag(110): a theoretical perspective
Autor/es:
N. CASTELLANI; L.A. MEIER; A. C. ROSSI
Lugar:
Montevideo
Reunión:
Congreso; 42nd International Congress of Theoretical Chemists of Latin Expression; 2016
Institución organizadora:
Universidad de la República
Resumen:
Dopamine (DA) is a neurotransmitter that plays an important physiologicalrole in the central nervous, renal and hormonal systems. It is therefore ofgreat medical and pharmacological interest to study chemical interactions inwhich this molecule is involved. Recently, the DA interaction with the surfaceof colloidal nanoparticles coated with a layer of Ag has been experimentallyinvestigated. In this work, the adsorption of dopamine and its zwitterionicspecies (ZDA) on the surface of Ag (110) was studied using the Vienna Ab InitioSimulation Package (VASP) in the context of the Density Functional Theory (DFT)formalism. The Ag(110) substrate is modeled using a slab of five metal layers,allowing the first atomic layer to be relaxed. Several geometricalconfigurations for the adsorption of DA and ZDA were considered, noting thatthe adsorption of these molecules in a horizontal orientation is more stable.The adsorption of ZDA on the surface of Ag(110) is benefited by 1.38 eV withrespect to DA. The presence of DA on Ag causes a local distortion of thesurface, as quantified by the analysis of deformation energies performed on thesystems studied. The adsorbate-substrate interaction was evaluated by computingthe electronic charge-density difference and the Voronoi atomic-charge changes of themolecule (ΔQ) with respect to separated fragments. It wasobserved that an important electron transfer occurs from the Ag substrate tothe molecules with a relevant electrostatic interaction. The vibrationfrequencies of DA and ZDA on Ag(110) were also considered. For comparison,complementary calculations were performed for DA and ZDA adsorbed on theAg(111) surface.