AVS 59th Annual International Symposium and Exhibition
    Electron Transport at the Nanoscale Focus Topic Thursday Sessions
       Session ET+SS+GR+SP-ThA

Paper ET+SS+GR+SP-ThA3
Electron Localization in Single Mixed-Valence Molecules

Thursday, November 1, 2012, 2:40 pm, Room 16

Session: Electron Transport at the Nanoscale: Molecules and Defects
Presenter: R.C. Quardokus, University of Notre Dame
Authors: R.C. Quardokus, University of Notre Dame
N.A. Wasio, University of Notre Dame
Y. Lu, University of Notre Dame
S.A. Kandel, University of Notre Dame
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Scanning tunneling microscopy (STM) is used to study two dinuclear organometallic molecules, meta-Fe2 and para-Fe2. These molecules share identical molecular formulas but differ in their positions of connectivity to the central phenyl ring. STM images of neutral meta-Fe2 and para-Fe2 show symmetrical distribution of electron density across the two metal centers. Chemical oxidation of these molecules leads to mixed-valence species. STM images of mixed-valence meta-Fe2 show an asymmetric distribution of the electron density between the two metal centers. Despite the greater distance between the two metal centers, the electron density remains symmetric in mixed-valence para-Fe2. Comparison with constrained density functional (CDFT) calculations leads to the conclusion that through-bond coupling of the two metal centers is more prevalent than through-space coupling. Further investigation of mixed-valence dinuclear organometallic molecules with asymmetric electron state density may open up the possibility for their use in molecularly based electronic devices.