title: Surface-enhanced raman scattering of pyrazine at the junction between two Ag20 nanoclusters.
abstract: In this work we present a detailed time-dependent density functional theory (TDDFT) investigation of the absorption and Raman spectra of a pyrazine molecule located at the junction between two Ag20 clusters. Surface-enhanced Raman scattering enhancements of the order of 10(6) have been found for the junction system, which are similar to enhancements of 10(5) found for individual silver nanoparticles. Surprisingly, the chemical enhancement is found to account for as much as 10(5), suggesting that this mechanism might be more important than previously believed, in particular for nanoparticle aggregates. Moreover, TDDFT calculations suggest that unlike larger nanoparticles, the junction between small Ag20 tetrahedral clusters does not provide an electromagnetic "hot spot".
authors.affiliation: Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA.
authors.forename: Lin Lin
authors.initials: LL
authors.lastname: Zhao
authors.forename: Lasse
authors.initials: L
authors.lastname: Jensen
authors.forename: George C
authors.initials: GC
authors.lastname: Schatz
mesh_terms: D003198:Computer Simulation; D008027:Light; D008956:Models, Chemical; D008958:Models, Molecular; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods; D010316:Particle Size; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*; D012542:Scattering, Radiation; D012834:Silver / Q000737:chemistry* / Q000528:radiation effects; D020349:Surface Plasmon Resonance / Q000379:methods*; D013499:Surface Properties
chemical_list: D012834:Silver