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Chemically Induced Electronic Excitations at Metal Surfaces
Brian Gergen,1Hermann Nienhaus,2W. Henry Weinberg,13Eric W. McFarland1*
The energy released in low-energy chemisorption or physisorption of
molecules on metal surfaces is usually expected to bedissipated by
surface vibrations (phonons). Theoretical descriptionsof
competing electronic excitations are incomplete, and experimentalobservation of excited charge carriers has been difficult exceptat
energies high enough to eject electrons from the surface. Weobserved
reaction-induced electron excitations during gas interactionswith
polycrystalline silver for a variety of species with adsorptionenergies between 0.2 and 3.5 electron volts. The probability ofexciting a detectable electron increases with increasing adsorptionenergy, and the measured time dependence of the electron currentcan be
understood in terms of the strength and mechanism of adsorption.
1 Department of Chemical Engineering,
University of California, Santa Barbara, CA 93106-5080, USA.
2 Laboratorium für Festkörperphysik,
Gerhard-Mercator-Universität, 47048 Duisburg, Germany.
3 Symyx Technologies, 3100 Central Expressway, Santa
Clara, CA 95051, USA.
*
To whom correspondence should be addressed. E-mail:
mcfar{at}engineering.ucsb.edu
Reactive and Nonreactive Scattering of H2 from a Metal Surface Is Electronically Adiabatic.
P. Nieto, E. Pijper, D. Barredo, G. Laurent, R. A. Olsen, E.-J. Baerends, G.-J. Kroes, and D. Farias (2006)
Science
312, 86-89
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