High temperature reaction rate coefficients derived from N-atom ARAS measurements and excimer photolysis of NO
✍ Scribed by D. F. Davidson; R. K. Hanson
- Publisher
- John Wiley and Sons
- Year
- 1990
- Tongue
- English
- Weight
- 959 KB
- Volume
- 22
- Category
- Article
- ISSN
- 0538-8066
No coin nor oath required. For personal study only.
✦ Synopsis
Mixtures of NO and NO/H2 in Ar were shock-heated and photolyzed with an ArF excimer laser. Measurements in these experiments of N-atom profiles using atomic resonance absorption spectrophotometry (ARAS) permitted the determination of two rate coefficients. The rate coefficient for the reaction (R1) N + NO-0 + Nz was found to be 4.29 x loL3 exp(-787/T) em3 mol-' see-' (520% at 1400 K t o ?lo% a t 3500 K). This is the first direct high temperature measurement of this rate coefficient in the exothermic direction. The rate coefficient for the reaction IR2)
N + Hz-H + NH was found to be 1.60 x 1014 exp(-12650/T) (235% from 1950 to 2850 K). To our knowledge, this is the first direct measurement of this rate coefficient.
A study of the N-atom ARAS absorption behavior revealed a noticeable pressure dependence, as well as a weak temperature dependence, in the Beer-Lambert law absorption coefficient. Proper consideration of these effects is important when the N-atom ARAS diagnostic is used for absolute concentration measurements.