Hannover 2013 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 26: Electronic Spectroscopy II

MO 26.2: Vortrag

Donnerstag, 21. März 2013, 14:15–14:30, F 107

Photoionization and Photodissociation of Halogenated Sulfur Compounds — •Beate Kieling, Loryn Fechner, Felix Gerke, Burkhard Langer, Roman Flesch, and Eckart Rühl — Physikalische Chemie, Freie Universität Berlin, Germany

Inner shell excitation of several sulfur(VI) and sulfur(IV) compounds containing halogens (SO₂F₂, SF₄, SOCl₂, SOClF, SOF₂) is studied in the S 2p regime by using high-resolution synchrotron radiation and time-of-flight mass spectrometry. The photoabsorption, photoionization, and subsequent fragmentation of these species is investigated. The main objective of this work is a comparison of these compounds with sulfur hexafluoride (SF₆).The electronic properties of SF6 are dominated by geometric cage effects leading to potential barriers with respect to photoionization. The interplay between outgoing and back-scattered electronic waves is reflected in the inner-shell spectra by (a) intense back-scattering shape resonances and (b) strongly suppressed Rydberg transitions. However, research regarding the inner-shell excitation of chemically related halogen-containing sulfur species is scarce. This is motivation for the present study on sulfur-halogen compounds that derive from SF₆ and SF₄ by substitution of fluorine atoms by oxygen and chlorine. Rydberg and shape resonances are observed which differ significantly from those in SF₆. In addition, photoelectron-photoion-photoion coincidence (PEPIPICO) spectra are discussed, yielding a consistent picture of decay processes occurring in the S 2p regime.