Imaging studies of the photodissociation of H{sub 2}S{sup +} cations. II

Journal Article · Fri Dec 14 04:00:00 EST 2007 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.2800565· OSTI ID:21024604

Webb, Alexander D; Kawanaka, Noboru; Dixon, Richard N; Ashfold, Michael N. R. ^[1]

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1. School of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom)

Ion imaging methods have been used to explore the photodissociation dynamics of state-selected H{sub 2}S{sup +} and D{sub 2}S{sup +} cations. Predissociation following one photon excitation to the A-tilde{sup 2}A{sub 1} state at wavelengths (385{<=}{lambda}{sub phot}{<=}420 nm) in the vicinity of the first dissociation threshold results in formation of ground state S{sup +} fragment ions; the partner H{sub 2}(D{sub 2}) fragments are deduced to be rotationally ''cold.'' Two photon dissociation processes are also observed, resonance enhanced at the energy of one absorbed photon by the predissociating A-tilde state levels. Two photon excitation at these wavelengths is deduced to populate an excited state of {sup 2}A{sub 1} symmetry, which dissociates to electronically excited S{sup +}({sup 2}D) products, together with vibrationally excited H{sub 2}(D{sub 2}) cofragments. Ground state SH{sup +}(SD{sup +}) fragments, attributable to a one photon dissociation process, are observed once {lambda}{sub phot}{<=}325 nm. Two photon induced production of SH{sup +}(SD{sup +}) fragments is also observed, at all wavelengths studied (i.e., at all {lambda}{sub phot}{<=}420 nm). These SH{sup +}(SD{sup +}) fragments are deduced to be formed in their singlet (i.e., a {sup 1}{delta} and b {sup 1}{sigma}{sup +}) excited states, with high levels of rotational excitation. The observed product branching and energy disposals are discussed within the context of the (limited) available knowledge relating to the excited electronic states of the H{sub 2}S{sup +} cation.

• OSTI ID: 21024604
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 22 Vol. 127; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
BRANCHING RATIO
CATIONS
DEUTERIUM COMPOUNDS
GROUND STATES
HYDROGEN
HYDROGEN SULFIDES
MULTI-PHOTON PROCESSES
PHOTOCHEMISTRY
PHOTOLYSIS
PHOTON-MOLECULE COLLISIONS
PHOTONS
PREDISSOCIATION
ROTATIONAL STATES
SULFUR IONS
VIBRATIONAL STATES
WAVELENGTHS