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Rotationally resolved vibrational overtone spectroscopy of hydrogen peroxide at chemically significant energies

Journal Article · · Journal of Chemical Physics; (USA)
DOI:https://doi.org/10.1063/1.459249· OSTI ID:6256039
;  [1]
  1. Department of Chemistry, University of Rochester, Rochester, NY 14627 (USA)

An infrared--optical double resonance scheme simplifies the room temperature 6{nu}{sub OH} vibrational overtone spectrum of hydrogen peroxide and prepares highly excited reactant molecules in single rotational states for unimolecular reaction studies. First, an optical parametric oscillator excites the OH asymmetric stretch ({nu}{sub 5}) and selects a single or small subset of rotational states. A visible dye laser pulse then promotes molecules from v{sub OH}=1 to v{sub OH}=6 where they subsequently dissociate to produce two OH fragments. A third laser detects the dissociation products {ital via} laser induced fluorescence. The rotationally resolved vibrational overtone spectra of hydrogen peroxide generated by scanning the visible dye laser frequency are assignable to a parallel band of a near prolate symmetric top. Linewidths of the individual rovibrational features range from 1--3 cm{sup {minus}1} but show no systematic dependence upon the rotational quantum numbers and are attributed predominantly to anharmonic coupling of the zeroth-order bright state to dark background states. The assignability of the double-resonance vibrational overtone spectra to {ital J} and {ital K} quantum numbers implies that {ital K} is conserved for {ital at} {ital least} a time determined by the linewidth of a single zeroth-order rovibrational feature.

OSTI ID:
6256039
Journal Information:
Journal of Chemical Physics; (USA), Journal Name: Journal of Chemical Physics; (USA) Journal Issue: 12 Vol. 93:12; ISSN JCPSA; ISSN 0021-9606
Country of Publication:
United States
Language:
English