Resonance structure in low-energy electron scattering from OCS

Hoffmann, T. H.; Hotop, H.; Allan, Michael

doi:10.1088/0953-4075/41/19/195202

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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

17.09.2008

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.

Faculty

Faculté des sciences et de médecine

Department

Département de Chimie

Language