Accession Number:

ADA409565

Title:

Experimental Study and Modeling of the Reaction H + O2 + M yields HO2 + M (M= Ar, N2, H2O) at Elevated Pressures and Temperatures Between 1050-1250K

Descriptive Note:

Technical paper

Corporate Author:

AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE WEST

Report Date:

2001-01-25

Pagination or Media Count:

21.0

Abstract:

The H O2 M yields HO2 M reaction was investigated at temperatures between 1050-1250 K and pressures from 7 to 152 bar behind reflected shock waves in gas mixtures of H2, 02, NO, and bath gases of Ar, N2, and H2O. Narrow linewidth laser absorption of NO2 at 472.7 nm was used to measure quasi-steady NO2 concentration plateaus in experiments designed to be sensitive only to the H 02 M yields HO2 M and the relatively well-known H NO2 yields NO OH and H 02 yields OH 0 reaction rates. The pressure dependence of the reaction was studied by measuring the fall-off of the reaction for M Ar over a 10-152 bar pressure range. A simple modified Hindered-Gorin model of the transition state is used in an RRKM analysis of the results to facilitate comparisons of this work with measurements from other researchers at lower pressures. The RRKM calculations can also be described, using the simple functional form suggested by Troe, with the following ksub infinitycu cm moleculeexp -1sexp -1 4.7x10exp -11T300exp .02 ksub 0Arcmexp 6 moleculeexp -2sexp -1 2.0x10exp -32T300exp -1.2 ksub 0N2cmexp 6 moleculeexp -2sexp -1 4.4 x 10exp -32T300exp -1.3 ksub 0H2Ocmexp 6 moleculeexp -2sexp-1 3.4 x 10exp -31T300exp -1.0 Fsub c 0.7 for Ar and N2 and 0.8 for H20. Measured values of the reaction rate for M Ar in the highest pressure experiments fall below both simple RRKM analysis and the more sophisticated treatment of Troe using an ab initio potential energy surface. Collision efficiencies of N2 and H20 relative to Ar at 1200K are 3.3 and 20 respectively.

Subject Categories:

  • Inorganic Chemistry
  • Physical Chemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE