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AuthorPopolan, Denisia M.dc.contributor.author
Date of accession2016-03-15T06:23:45Zdc.date.accessioned
Available in OPARU since2016-03-15T06:23:45Zdc.date.available
Year of creation2010dc.date.created
AbstractThe aim of the present work was the investigation of the size and composition dependent chemistry of free, mass-selected gold, silver, and binary silver-gold clusters. Temperature dependent reactivity measurements were performed to determine the binding energies of CO to the binary silver-gold trimer and pentamer clusters. The CO binding energies to AgnAum+ (n + m = 3, 5) clusters were found to decrease with increasing number of silver atoms. More strikingly, after the adsorption of the fourth CO to Au5+ and third CO to Ag5+, respectively, a pronounced decrease in the binding energies of further CO molecules was observed. In conjunction with theoretical simulations performed by Vlasta Bonacic-Koutecký, it could be demonstrated that this observation can be explained by a CO-induced structural transformation yielding more compact metal clusters geometries. While gold and silver cluster cations were found to be completely inert towards molecular oxygen under our experimental conditions, it was possible to produce metal-oxide clusters through the reaction with nitrous oxide. Experimental evidence was obtained for the occurrence of a complete catalytic CO oxidation cycle promoted by silver and gold oxide, which was generated by reaction with N2O. Furthermore, the reactions of size-selected gold and silver clusters cations Agn+ and Aun+ (n = 3, 5) with C6H6 and with a mixture of C6H6 and CO were investigated. In the case of silver clusters photodissociation experiments at 353 and 393 nm, respectively, provided indications for a charge transfer induced fragmentation. In particular, for Ag5(C6H6)+ the femtosecond time resolved fragmentation dynamics could be measured. In a final series of experiments the gas phase reactions of gold cluster cations, in this case with CH3Br, could be directly compared to similar experiments with metal oxide supported gold clusters that were obtained in the same apparatus.dc.description.abstract
Languageendc.language.iso
PublisherUniversität Ulmdc.publisher
LicenseStandard (Fassung vom 01.10.2008)dc.rights
Link to license texthttps://oparu.uni-ulm.de/xmlui/license_v2dc.rights.uri
KeywordCharge-transfer reactiondc.subject
KeywordCluster reactivitydc.subject
KeywordFemtosecond dynamicsdc.subject
KeywordIon trapdc.subject
KeywordSilver-gold clustersdc.subject
Dewey Decimal GroupDDC 540 / Chemistry & allied sciencesdc.subject.ddc
LCSHCatalysisdc.subject.lcsh
LCSHGold. Clustersdc.subject.lcsh
LCSHSilver. Clustersdc.subject.lcsh
TitleSize and composition dependent reaction kinetics and femtosecond photodissociation dynamics of noble metal cluster complexesdc.title
Resource typeDissertationdc.type
DOIhttp://dx.doi.org/10.18725/OPARU-1904dc.identifier.doi
PPN656472324dc.identifier.ppn
URNhttp://nbn-resolving.de/urn:nbn:de:bsz:289-vts-75875dc.identifier.urn
GNDEdelmetallkomplexedc.subject.gnd
GNDIonenfalledc.subject.gnd
GNDPhotodissoziationdc.subject.gnd
FacultyFakultät für Naturwissenschaftenuulm.affiliationGeneral
Date of activation2011-04-04T14:54:05Zuulm.freischaltungVTS
Peer reviewneinuulm.peerReview
Shelfmark print versionZ: J-H 14.094; W: W-H 12.558uulm.shelfmark
DCMI TypeTextuulm.typeDCMI
VTS-ID7587uulm.vtsID
CategoryPublikationenuulm.category
University Bibliographyjauulm.unibibliographie


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