Journal article

Resonance structure in low-energy electron scattering from OCS

  • Hoffmann, T. H. Fachbereich Physik, Technische Universität Kaiserslautern, Germany
  • Hotop, H. Fachbereich Physik, Technische Universität Kaiserslautern, Germany
  • Allan, Michael Department of Chemistry, University of Fribourg, Switzerland
Published in:
  • Journal of Physics B: Atomic, Molecular and Optical Physics. - 2008, vol. 41, no. 9, p. 195202
English Energy-dependent absolute angle-differential cross sections (θ = 135°) for elastic and vibrationally inelastic electron scattering from OCS molecules have been investigated at high resolution (13 meV). The elastic cross section, reported over the range E= 0.06–20 eV, exhibits a deep Ramsauer–Townsend minimum near 0.55 eV and the π*(1.2 eV) and σ*(3.8 eV) resonances known from earlier experimental and theoretical work. The excitation functions for vibrational excitation (VE) of the fundamental CS stretch (1 0 0), the CO stretch (0 0 1) as well as for the fundamental and harmonics of the bending (0 n 0) mode are reported from threshold up to E = 8 eV. VE is mediated—in part in a mode-selective way—by threshold peaks and the higher lying resonances. The selectivity in the threshold region can be rationalized in terms of symmetry arguments where the ²Σ virtual state excites preferentially the σ vibrational states with even quanta of bending vibration over the π vibrational states with odd quanta of bending vibration. The σ*CS resonance is essentially inactive in VE of the CO stretch and the bending mode.
Faculté des sciences et de médecine
Département de Chimie
  • English
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