title: Geometrical Structures of Partially Oxidized Rhodium Cluster Cations, Rh6Om+(m = 4, 5, 6), Revealed by Infrared Multiple Photon Dissociation Spectroscopy.
abstract: Infrared multiple photon dissociation (IRMPD) spectra of Rh6Om+(m = 4-10) are obtained in the 300-1000 cm-1spectral range using the free electron laser for infrared experiments (FELIX) via dissociation of Rh6Om+or Rh6Om+-Ar complexes. The spectra are compared with the calculated spectra of several stable geometries obtained by density functional theory (DFT) structural optimization. The spectrum for Rh6O4+shows prominent bands at 620 and 690 cm-1and is assigned to a capped-square pyramidal Rh atom geometry with three bridging O atoms and one O atom in a hollow site. Rh6O5+displays bands at 460, 630, 690, and 860 cm-1and has a prismatic Rh geometry with three bridging O atoms and two O atoms in a hollow site. Rh6O6+shows three intense bands around 600-750 cm-1and multiple weak bands in the range of 350-550 cm-1. This species has a prismatic Rh geometry with four bridging O atoms and two O atoms in a hollow site. Considering that Rh6Om+(m ≤ 3) adopts tetragonal bipyramidal Rh6structures, the change at m = 4 to capped bipyramidal and at m = 5 to prismatic geometries results in a reduction of the number of triangular hollow sites. Since NO preferentially binds on a triangular hollow site through the N atom, the geometry change lowers the possibility of NO dissociative adsorption.
authors.affiliation: Department of Basic Science, School of Arts and Sciences, The University of Tokyo , Komaba, Meguro, Tokyo 153-8902, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Koyama
authors.affiliation: Department of Basic Science, School of Arts and Sciences, The University of Tokyo , Komaba, Meguro, Tokyo 153-8902, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Nagata
authors.affiliation: Department of Basic Science, School of Arts and Sciences, The University of Tokyo , Komaba, Meguro, Tokyo 153-8902, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kudoh
authors.affiliation: Department of Basic Science, School of Arts and Sciences, The University of Tokyo , Komaba, Meguro, Tokyo 153-8902, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Miyajima
authors.affiliation: FELIX Laboratory, Institute for Molecules and Materials, Radboud University , Toernooiveld 7c, 6525 ED Nijmegen, The Netherlands.
authors.forename: Douwe M M
authors.initials: DM
authors.lastname: Huitema
authors.affiliation: FELIX Laboratory, Institute for Molecules and Materials, Radboud University , Toernooiveld 7c, 6525 ED Nijmegen, The Netherlands.
authors.forename: Valeriy
authors.initials: V
authors.lastname: Chernyy
authors.affiliation: FELIX Laboratory, Institute for Molecules and Materials, Radboud University , Toernooiveld 7c, 6525 ED Nijmegen, The Netherlands.
authors.forename: Joost M
authors.initials: JM
authors.lastname: Bakker
authors.affiliation: Department of Basic Science, School of Arts and Sciences, The University of Tokyo , Komaba, Meguro, Tokyo 153-8902, Japan.
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Mafuné