Pressure and temperature dependence of the reaction NO/sub 2/ + NO/sub 3/ + M. -->. N/sub 2/O/sub 5/ + M

Journal Article · Thu Sep 13 04:00:00 EDT 1984 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j150663a037· OSTI ID:6053496

Kircher, C C; Margitan, J J; Sander, S P

The kinetics of the reaction NO/sub 2/ + NO/sub 3/ + M ..-->.. N/sub 2/O/sub 5/ + M (1) were studied with flash photolysis/visible absorption by monitoring the disappearance of NO/sub 3/ under pseudo-first-order conditions over the temperature range 236-358 K and pressure range 20-700 torr of M (helium and nitrogen). Reaction 1 was found to be in the falloff region between second- and third-order kinetics in this range. Falloff parameters were obtained by fitting the experimental data to the falloff equation of Troe and co-workers. When one uses a published temperature-dependent broadening factor (F/sub c/), the data are described by k/sub 0/(N/sub 2/) = 4.5 x 10/sup -30/ cm/sub 6/ molecule/sup -1/ s/sup -1/ and k/sub infinity/ - 1.65 x 10/sup -12/ cm/sup 3/ molecule/sup -1/ s/sup -1/ at 298 K with T dependencies of T/sup -3.4/ and T/sup -0.4/ for k/sub 0/ and K/sub infinity/, respectively. This expression was used in conjunction with recent measurements of the rate constant for N/sub 2/O/sub 5/ thermal decomposition to obtain an improved measurement ..delta..H/sub f//sup 0/ (298) for NO/sub 3/, which was determined to be 17.3 +/- 0.7 kcal mol/sup -1/. From these data the recommended equilibrium constant expression is K/sub eq/ = k/sub 1//K/sub -1/ = 2.31 x 10/sup -8/ exp(11350/T) (atm/sup -1/). 31 references, 6 figures, 2 tables.

• Research Organization: California Inst. of Tech., Pasadena
• OSTI ID: 6053496
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 88:19; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
500200 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ABSORPTION SPECTROSCOPY
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DATA
DATA ANALYSIS
DECOMPOSITION
ELEMENTS
EXPERIMENTAL DATA
FLUIDS
GASES
HELIUM
INFORMATION
KINETICS
LOW PRESSURE
LOW TEMPERATURE
MEDIUM TEMPERATURE
NITRATES
NITROGEN
NITROGEN COMPOUNDS
NITROGEN DIOXIDE
NITROGEN OXIDES
NONMETALS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
PRESSURE DEPENDENCE
RADICALS
RARE GASES
REACTION KINETICS
SAMPLE PREPARATION
SPECTROSCOPY
TEMPERATURE DEPENDENCE
TIME DEPENDENCE