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Rate constant for the reaction H + NH/sub 3/ over the temperature range 750-1777 K

Conference · · J. Phys. Chem.; (United States)
OSTI ID:6038298

The rate constant for the reaction of atomic hydrogen with ammonia has been measured over the temperature range 908-1777 K by the flash photolysis-shock tube technique using atomic resonance absorption to monitor (H)/sub t/. The Arrhenius rate expression is k/sub 1/ = (3.02 +/- 0.30) x 10/sup -10/ exp(-8067 +/- 117/T) cm/sup 3/ molecule/sup -1/ s/sup -1/. The rate constant was also measured at 750 K by the flash photolysis-resonance fluorescence (FP-RF) method: k/sub 1/ = (1.27 +/- 0.18) x 10/sup -14/ cm/sup 3/ molecule /sup -1/ s/sup -1/. Detailed analysis of the kinetic data revealed that the Arrhenius plot is slightly nonlinear, and the shock tube data can be expressed by the three-parameter equation k/sub 1/ = 1.06 x 10/sup -18/T/sup 2.39 exp(-5119/T) cm/sup 3/ molecule/sup -1/ s/sup -1/. This result is compared to that from a theoretical calculation, k/sub 1/ = 1.16 x 10/sup -17/ T/sup 2.17 exp (-6268/T) cm/sup 3/ molecule/sup -1/ s/sup -1/ for 600 less than or equal to T less than or equal to 2600 K. Accepting the nonlinearity of the Arrhenius plot, the rate constant results from the two independent experimental techniques are in satisfactory agreement. 13 references, 2 figures, 3 tables.

Research Organization:
Brookhaven National Lab., Upton, NY
DOE Contract Number:
AC02-76CH00016
OSTI ID:
6038298
Journal Information:
J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 90:3; ISSN JPCHA
Country of Publication:
United States
Language:
English