Kinetics of the reaction of OH with HI between 246 and 353 K
- Max-Planck-Inst. fuer Chemie, Mainz (Germany). Div. of Atmospheric Chemistry
Iodine chemistry is believed to play a role in tropospheric, and, potentially, also stratospheric ozone loss. The laser-flash photolysis technique combined with resonance fluorescence detection of OH was used to investigate the kinetics of the title reaction at temperatures between 246 and 353 K and at a total pressure of 75 {+-} 1 Torr Ar. Under these conditions the rate coefficient shows a negative temperature dependence which is described by {kappa}{sub 4}(246--353 K) = 7.0{sub {minus}0.4}{sup +1.9} {times} 10{sup {minus}11}(T/298){sup 1.5{+-}0.5} cm{sup 3} s{sup {minus}1}. Both the large rate coefficient and trends in the reactivity of OH with HCl, HBr, and HI are suggestive of a reaction mechanism that proceeds without a significant activation barrier. The room temperature (294 K) rate constant is {kappa}{sub 4} = 6.5{sub {minus}0.4}{sup +2} {times} 10{sup {minus}11} cm{sup 3} s{sup {minus}1}, which is significantly larger than previous measurements. Reasons for this difference and the implications of the new rate coefficients for the lifetime of HI in the atmosphere are discussed.
- OSTI ID:
- 347660
- Journal Information:
- Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory, Journal Name: Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory Journal Issue: 15 Vol. 103; ISSN 1089-5639; ISSN JPCAFH
- Country of Publication:
- United States
- Language:
- English
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