Vibrational scattering anisotropy in O-2-dynamics beyond the Born-Oppenheimer approximation
2012 (English)In: New Journal of Physics, ISSN 1367-2630, Vol. 14, 113018- p.Article in journal (Refereed) Published
Born-Oppenheimer and Franck-Condon approximations are two major concepts in the interpretation of electronic excitations and modeling of spectroscopic data in the gas and condensed phases. We report large variations of the anisotropy parameter (beta) for the fully resolved vibrational sub-states of the X-2 Pi(g) electronic ground state of O-2(+) populated by participator resonant Auger decay following excitations of K-shell electrons into the sigma(star) resonance by monochromatic x-rays. Decay spectra for light polarization directions parallel and perpendicular to the electron detection axis recorded at four different excitation energies in the vicinity of the O 1s -> sigma(star) transition are presented. Breakdown of the Born-Oppenheimer approximation is for the first time selectively observed for the lower vibrational sub-states, where two quantum paths-resonant and direct-leading to the same final cationic state exist. The higher vibrational sub-states can only be populated by resonant photoemission; hence no interference between these channels can occur.
Place, publisher, year, edition, pages
2012. Vol. 14, 113018- p.
Auger-Electron Spectra, Ray Raman-Scattering, Cross-Sections, Coincidence Spectroscopy, Angular-Distribution, Molecular-Dynamics, Pi-Asterisk, K-Edge, N 1s, Resolution
IdentifiersURN: urn:nbn:se:kth:diva-107614DOI: 10.1088/1367-2630/14/11/113018ISI: 000311094500002ScopusID: 2-s2.0-84870427916OAI: oai:DiVA.org:kth-107614DiVA: diva2:577747
FunderEU, European Research Council, 252781Swedish Research Council, 623-2009-779Knut and Alice Wallenberg Foundation
QC 201212172012-12-172012-12-142012-12-17Bibliographically approved