title: Spectroscopy of isolated, mass-selected tryptophan-Ag3 complexes: a model for photoabsorption enhancement in nanoparticle-biomolecule hybrid systems.
abstract: We wish to show that gas-phase studies of small metal cluster-biomolecule complexes provide fundamental insights into the mechanism leading to enhanced optical absorption in nanoparticle-biomolecular hybrid systems. Here we present, for the first time, a joint experimental and theoretical study of photoabsorption and photofragmentation of the silver trimer-tryptophan cation complex ([Trp.Ag3]+). We demonstrate that binding the metal cluster to a biomolecule leads to a remarkably high optical absorption as compared to the bare tryptophan or the [Trp.Ag]+ complex. As calculations show this arises due to coupling between the excitations in the metallic subunit with a charge transfer excitation to the tryptophan molecule.
authors.affiliation: Laboratoire de Spectrométrie ionique et moléculaire UMR 5579, Université Lyon 1 and CNRS, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne cedex, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Compagnon
authors.forename: Thibault
authors.initials: T
authors.lastname: Tabarin
authors.forename: Rodolphe
authors.initials: R
authors.lastname: Antoine
authors.forename: Michel
authors.initials: M
authors.lastname: Broyer
authors.forename: Philippe
authors.initials: P
authors.lastname: Dugourd
authors.forename: Roland
authors.initials: R
authors.lastname: Mitrić
authors.forename: Jens
authors.initials: J
authors.lastname: Petersen
authors.forename: Vlasta
authors.initials: V
authors.lastname: Bonacić-Koutecký
mesh_terms: D008954:Models, Biological; D008958:Models, Molecular; D008968:Molecular Conformation; D008970:Molecular Weight; D053758:Nanoparticles / Q000737:chemistry*; D010777:Photochemistry; D012834:Silver / Q000737:chemistry*; D013057:Spectrum Analysis; D014364:Tryptophan / Q000737:chemistry*
chemical_list: D012834:Silver; D014364:Tryptophan