The production and characterization by resonance enhanced multiphoton ionization of H sub 2 ( v =10--14) from photodissociation of H sub 2 S

Journal Article · Wed Nov 15 04:00:00 EST 1989 · Journal of Chemical Physics; (USA)

DOI:https://doi.org/10.1063/1.457430· OSTI ID:5356032

Steadman, J; Baer, T ^[1]

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1. Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290 (US)

The excitation of H{sub 2}S at 66 000 cm{sup {minus}1} by two-photon absorption is shown to produce significant quantities of H{sub 2} molecules in very high vibrational, but low rotational levels. The vibrationally excited H{sub 2} has been identified by a 2+1+1 resonance enhanced multiphoton ionization (REMPI) process in whch the {ital {tilde E}},{ital {tilde F}} state is excited as an intermediate state. The major contribution of this double well state comes from the outer {ital {tilde F}} well because of the large H{sub 2} bond distance in the nascent H{sub 2}({ital v}) photoproduct. Excitation of the {ital {tilde E}},{ital {tilde F}} state by a 291 nm photon dissociates the molecule to the H+H*({ital n}=3) products, and the excited atom is then ionized by a fourth photon. The analysis of the photoelectron spectra (PES) demonstrates that the intermediate H{sub 2}S* molecule preferentially dissociates to vibrationally excited H{sub 2} molecules rather than ionizing by the absorption of an additional photon. It appears likely that the photodissociation of H{sub 2}S is a practical method for producing highly vibrationally excited, but rotationally cool, H{sub 2} molecules for further dynamical studies.

• OSTI ID: 5356032
• Journal Information: Journal of Chemical Physics; (USA), Journal Name: Journal of Chemical Physics; (USA) Vol. 91:10; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
CHALCOGENIDES
CHEMICAL REACTIONS
DECOMPOSITION
ELEMENTS
HYDROGEN
HYDROGEN COMPOUNDS
HYDROGEN SULFIDES
IONIZATION
MULTI-PHOTON PROCESSES
NONMETALS
PHOTOCHEMICAL REACTIONS
PHOTOIONIZATION
PHOTOLYSIS
RESONANCE
SULFIDES
SULFUR COMPOUNDS