title: Chemical Raman enhancement of organic adsorbates on metal surfaces.
abstract: Using first-principles theory and experiments, chemical contributions to surface-enhanced Raman spectroscopy for a well-studied organic molecule, benzene thiol, chemisorbed on planar Au(111) surfaces are explained and quantified. Density functional theory calculations of the static Raman tensor demonstrate a strong mode-dependent modification of benzene thiol Raman spectra by Au substrates. Raman active modes with the largest enhancements result from stronger contributions from Au to their electron-vibron coupling, as quantified through a deformation potential. A straightforward and general analysis is introduced to extract chemical enhancement from experiments for specific vibrational modes; measured values are in excellent agreement with our calculations.
authors.affiliation: Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley California 94720, USA.
authors.forename: A T
authors.initials: AT
authors.lastname: Zayak
authors.forename: Y S
authors.initials: YS
authors.lastname: Hu
authors.forename: H
authors.initials: H
authors.lastname: Choo
authors.forename: J
authors.initials: J
authors.lastname: Bokor
authors.forename: S
authors.initials: S
authors.lastname: Cabrini
authors.forename: P J
authors.initials: PJ
authors.lastname: Schuck
authors.forename: J B
authors.initials: JB
authors.lastname: Neaton
mesh_terms: D000327:Adsorption; D006046:Gold / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D010636:Phenols / Q000737:chemistry*; D011789:Quantum Theory; D013059:Spectrum Analysis, Raman; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D010636:Phenols; D013438:Sulfhydryl Compounds; D006046:Gold; C042983:thiophenol