München 2004 – scientific programme
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MO: Molekülphysik
MO 9: Photoelektronenspektroskopie
MO 9.3: Talk
Monday, March 22, 2004, 17:00–17:15, HS 332
Probing the Degree of Core Hole Localization in Isotope Substituted N2 via Photoelectron Spectroscopy — •D. Rolles1, M. Braune1, S. Cvejanovic1,2, R. Hentges1, S. Korica1, B. Langer1,3, G. Prümper1, A. Reinköster1, J. Viefhaus1, and U. Becker1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany — 2University of Rijeka, 51000 Rijeka, Croatia — 3Max-Born-Institut, 12489 Berlin, Germany
The localization or delocalization of core holes in photoexcited homonuclear molecules has been a subject of fierce debate over several decades. Recent studies have found convincing evidence for both localization as well as delocalization in different systems [1,2,3]. Examining the showcase molecule N2, we prove that the core hole (after 1s ionization) is indeed delocalized and the photoelectron is emitted coherently from both centers. However, we find that the hole can be partially localized and the degree of coherence can be reduced by breaking the inversion symmetry through isotope substitution. The result is a mixing of the 1 σ gerade and ungerade symmetry components leading to a change of the g/u-resolved cross section and photoelectron angular distribution by several percent. To our knowledge, this is the first time that such an isotope effect has been observed in core-level photoelectron spectroscopy.
[1] U. Hergenhahn et al., J. Phys. Chem. A 105, 5704 (2001).
[2] O. Björneholm et al., Phys. Rev. Lett. 84, 2826 (2000).
[3] R. Hentges et al., Verhandlungen der DPG (2004)