Fourier transform infrared emission study of the mechanism and dynamics of HOI formed in the reaction of alkyl iodides with O({sup 3}P)

Journal Article · Sat Mar 01 04:00:00 EST 1997 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.473510· OSTI ID:467241

Loomis, R A; Klaassen, J J; Lindner, J; Christopher, P G; Leone, S R ^[1]

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1. JILA, National Institute of Standards and Technology and University of Colorado, and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440 (United States)

Vibrationally excited hypoiodous acid (HOI) is observed as a product in the reaction of alkyl iodides with O({sup 3}P). Fourier transform infrared emission techniques are used to detect the excited {nu}{sub 1}, OH, stretch of the HOI product, to determine the mechanism of HOI production, and to measure the vibrational product state distributions. The HOI product is formed by O atom reaction with two-carbon and larger straight or branched chain alkyl iodides and cyclic alkyl iodides, e.g., C{sub 2}H{sub 5}I, n-C{sub 3}H{sub 7}I, i-C{sub 3}H{sub 7}I, (CH{sub 3}){sub 3}CI, n-C{sub 6}H{sub 13}I, and c-C{sub 6}H{sub 11}I, but not with CH{sub 3}I. Experiments with selectively deuterated ethyl iodides provide direct evidence that HOI is formed in a beta-elimination mechanism involving a five-membered ring transition state. The O atom attacks the iodine and then abstracts a hydrogen from the beta carbon during the lifetime of the complex. Time-resolved experiments allow the extraction of nascent vibrational state distributions for the {nu}{sub 1} stretch of HOI (v=1:v=2:v=3) using different alkyl iodides and assuming the radiative rates are given by A{sub {nu}{r_arrow}{nu}{minus}1}=vA{sub 1{r_arrow}0}: C{sub 2}H{sub 5}I, 0.53(4):0.39(3):0.08(3); n-C{sub 3}H{sub 7}I, 0.61(6):0.34(5):0.05(2); and i-C{sub 3}H{sub 7}I, 0.54(6):0.38(4):0.08(3). These distributions are nonstatistical with the v=2 states having only slightly less population than those with v=1. For product molecules with up to three quanta of {nu}{sub 1} excitation, more than 50{percent} of the reaction exothermicity is deposited into the OH stretch. {copyright} {ital 1997 American Institute of Physics.}

• OSTI ID: 467241
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 10 Vol. 106; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ALKYL RADICALS
CHEMICAL REACTION KINETICS
DYNAMICS
FOURIER TRANSFORMATION
HYDROXYL RADICALS
INFRARED SPECTRA
IODIDES
ORGANIC COMPOUNDS
OXYGEN
VIBRATIONAL STATES