Dresden 2011 – scientific programme
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O: Fachverband Oberflächenphysik
O 7: Surface Dynamics I
O 7.5: Talk
Monday, March 14, 2011, 12:15–12:30, WIL C107
Kinetic energy distributions of vibrationally promoted electrons at metal surfaces: Comparison of different initial vibrational states — •Tim Schäfer1, Jerry Larue2, Daniel Matsiev2, Luis Velarde2, Daniel J. Auerbach2, and Alec M. Wodtke1 — 1Georg-August Universität Göttingen, Institut für Physikalische Chemie, Tammannstr.6, 37077 Göttingen, Germany — 2Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106-9510, USA
Kinetic energy distributions of exoelectrons produced by collisions of highly vibrationally excited NO molecules with a low work function Cs dosed Au surface were studied. The NO molecules were optically prepared in X2Π1/2 (v=16) and X2Π1/2 (v=22) using Stimulated Emission Pumping (SEP) and the electron energy distributions were measured with a home-built retarding field electron energy analyzer. The results obtained by these experiments indicate that many quanta, as high as Δ v =17 for v=22, can be transferred to a single electron. The most probable transfer of vibrational quanta is Δ v =11 for NO(v=16) and Δ v = 12 for NO(v=22) and is in qualitatively good agreement with previous studies. In addition to the results obtained by the experiments with the SEP prepared molecules the study of vibrationally excited molecules produced by spontaneous emission (Franck-Condon pumping, FCP) supports the overall conclusion: The kinetic energy distribution of vibrationally promoted electrons strongly suggests a coupling of multiple vibrational quanta to a single electron and cannot be explained in a simple adiabatic picture.