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Berlin, Germany

Pacchioni G.,University of Milan Bicocca | Freund H.,Fritz Haber Insitut der MPG
Chemical Reviews | Year: 2013

Electron transfer (ET) is a fundamental process in physics, chemistry, and biology. Charge transfer determines phenomena like oxidation and reduction, bond activation and bond breaking in chemical reactions, formation of radical species, and charge transport and charge trapping in nanoelectronic devices, just to mention a few examples. ET processes are the basis of technologically relevant fields. One of the best characterized systems is MgO, a simple stoichiometric binary oxide with rock-salt structure, which exhibits well-defined surfaces and is stable under operating conditions. Despite this apparent simplicity, a lot of work spanning several decades has been necessary to unravel the atomistic details of reactivity of this material. When going from a (001) single crystal surface, where the number of such sites is negligible, to a powder sample, where these sites represent a significant fraction of the total exposed surface, one observes a complete change of reactivity, from totally inert to highly reactive. Source

Lian J.C.,Fritz Haber Insitut der MPG | Lian J.C.,CAS Institute of Physics | Kieseritzky E.,Fritz Haber Insitut der MPG | Gonchar A.,Fritz Haber Insitut der MPG | And 4 more authors.
Journal of Physical Chemistry C | Year: 2010

The adsorption of N2O on the surface of MgO(001) thin films has been studied at low temperature (60 K) using infrared reflection-absorption spectroscopy (IRAS) and temperature-programmed desorption (TPD). The observed infrared spectrum consists of several components indicating different adsorption sites for N2O. The different IR peaks can be related to particular thermal desorption features by combining the TPD spectra with temperature-dependent infrared measurement. By comparing spectra from films with different roughness and different supports, a band at 2236 cm-1 can be assigned to N2O adsorbed on the MgO terraces, while peaks at the higher frequency are assigned to molecules adsorbed on low-coordinated sites. © 2010 American Chemical Society. Source

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