title: Charge-mediated adsorption behavior of CO on MgO-supported Au clusters.
abstract: The CO binding behavior to gold particles supported on MgO thin films has been analyzed with scanning tunneling microscopy (STM) and infrared spectroscopy (IRAS). The ad-particles accommodate excess electrons that originate either from a charge transfer through the thin oxide film or from a local interaction with electron-rich oxide defects that act as Au nucleation centers. The enhanced electron density in the Au aggregates affects both the spatial distribution and the vibrational properties of adsorbed CO species. Whereas preferential CO attachment to the chemically unsaturated and electron-rich boundary sites of the Au islands is deduced from the STM data, a continuous downshift of the CO stretching frequency with decreasing particle size is observed in IRAS. Both results are interpreted in the light of CO adsorption to negatively charged metal aggregates and used to draw general conclusions on the interplay between charge and adsorption properties of confined metal systems.
authors.affiliation: Fritz-Haber-Institut der MPG, Faradayweg 4-6, D-14195 Berlin, Germany.
authors.forename: Xiao
authors.initials: X
authors.lastname: Lin
authors.forename: Bing
authors.initials: B
authors.lastname: Yang
authors.forename: Hadj-Mohamed
authors.initials: HM
authors.lastname: Benia
authors.forename: Philipp
authors.initials: P
authors.lastname: Myrach
authors.forename: Maxim
authors.initials: M
authors.lastname: Yulikov
authors.forename: Andreas
authors.initials: A
authors.lastname: Aumer
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Brown
authors.forename: Martin
authors.initials: M
authors.lastname: Sterrer
authors.forename: Oleksander
authors.initials: O
authors.lastname: Bondarchuk
authors.forename: Esther
authors.initials: E
authors.lastname: Kieseritzky
authors.forename: Jan
authors.initials: J
authors.lastname: Rocker
authors.forename: Thomas
authors.initials: T
authors.lastname: Risse
authors.forename: Hong-Jun
authors.initials: HJ
authors.lastname: Gao
authors.forename: Niklas
authors.initials: N
authors.lastname: Nilius
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Freund