The catalytic properties of gold nanoparticles are determined by their electronic and geometric structures. We revealed the geometries of several small neutral gold clusters in the gas phase by using vibrational spectroscopy between 47 and 220 wavenumbers. A two-dimensional structure for neutral Au 7 and a pyramidal structure for neutral Au 20 can be unambiguously assigned. The reduction of the symmetry when a corner atom is cut from the tetrahedral Au 20 cluster is directly reflected in the vibrational spectrum of Au 19 .

We present gas-phase infrared spectra for small silicon cluster cations possessing between 6 and 21 atoms. Infrared multiple photon dissociation (IR-MPD) of these clusters complexed with a xenon atom is employed to obtain their vibrational spectra. These vibrational spectra give for the first time experimental data capable of distinguishing the exact internal structures of the silicon cluster cations. By comparing the experimental spectra with theoretical predictions based on density functional theory (DFT), unambiguous structural assignments for most of the Si(n)(+) clusters in this size range have been made. In particular, for Si(8)(+) an edge-capped pentagonal bypriamid structure, hitherto not considered, was assigned. These structural assignments provide direct experimental evidence for a cluster growth motif starting with a pentagonal bipyramid building block and changing to a trigonal prism for larger clusters.

Access and use of this website and the material on it are subject to the Terms and Conditions set forth at Gold cluster carbonyls: saturated adsorption of CO on gold cluster cations, vibrational spectroscopy, and implications for their structures Fielicke, A.; vonHelden, G.; Meijer, G Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://doi.org/10.1021/ja0509230Journal of the American Chemical Society, 127, 23, pp. 8416-8423, 2005-06- Abstract:We report on the interaction of carbon monoxide with cationic gold clusters in the gas phase. Successive adsorption of CO molecules on the Aun + clusters proceeds until a cluster size specific saturation coverage is reached. Structural information for the bare gold clusters is obtained by comparing the saturation stoichiometry with the number of available equivalent sites presented by candidate structures of Au n + . Our findings are in agreement with the planar structures of the Aun + cluster cations with n e 7 that are suggested by ion mobility experiments [Gilb, S.; Weis, P.; Furche, F.; Ahlrichs, R.; Kappes, M. M. J. Chem. Phys. 2001, 116, 4094]. By inference we also establish the structure of the saturated Aun(CO)m + complexes. In certain cases we find evidence suggesting that successive adsorption of CO can distort the metal cluster framework. In addition, the vibrational spectra of the Au n(CO)m + complexes in both the CO stretching region and in the region of the Au-C stretch and the Au-C-O bend are measured using infrared photodepletion spectroscopy. The spectra further aid in the structure determination of Aun + , provide information on the structure of the Aun + -CO complexes, and can be compared with spectra of CO adsorbates on deposited clusters or surfaces.