The nitrate radical: Physics, chemistry, and the atmosphere

Reliable kinetics data are necessary input for models describing the decomposition of gases in electric discharge or electron-beam devices In this second part of a continuing series, we provide a core database describing the dominant reactions of neutral species in nonthermal low temperature (300–700K) pulsed plasmas containing humid air Recommended rate constants and extrapolation methods are provided in a manner to facilitate prediction of reactivities as a function of temperature and pressure

Chemical Kinetics Database and Predictive Schemes for Nonthermal Humid Air Plasma Chemistry. Part II. Neutral Species Reactions

The kinetics of the gas-phase reactions of SO3 with H2O and D2O were studied over the temperature range 250−360 K in N2 with a laminar flow reactor coupled to a chemical ionization mass spectrometer. The SO3 loss is second order in the water concentration, is independent of pressure (20−80 Torr N2, 300 K), and has a strong negative temperature dependence and a significant H/D isotope effect (kH2O ≈ 2kD2O). The yield of sulfuric acid is 1.0 ± 0.5 per SO3 consumed. These observations are consistent with the rapid association of SO3 and H2O to form the adduct H2OSO3 which reacts with water to produce sulfuric acid. The first-order rate coefficients for loss of SO3 by reaction with H2O and D2O are given by kI(s-1) = (2.26 ± 0.85) × 10-43T exp((6544 ± 106)/T)[H2O]2 and (9.45 ± 2.68) × 10-44T exp((6573 ± 82)/T)[D2O]2, where T ≡ K and [H2O, D2O] ≡ molecule cm-3. The errors are the uncertainty at the 95% confidence level for precision only. Analysis of the temperature dependence of the SO3 loss yields an upper li...

Kinetics and Products of the Gas-Phase Reaction of SO3 with Water

[1] Submicron particle-size distributions were measured with 10-s resolution aboard the National Oceanic and Atmospheric Administration WP-3D Orion research aircraft in the plumes downwind of coal-fired power generation plants in the eastern United States and the urban areas of Nashville, Tennessee, and Atlanta, Georgia. Recently formed particles were present at the edges of some power plant plumes within 2 hours of emission, coinciding with OH maxima predicted by a numerical plume photochemistry model. Clearly detectable increases in particle volume (mass) concentration with increasing plume age, indicating gas-to-particle conversion, were found in only those plumes from sources that emit substantial quantities of SO2. The observed growth in particulate volume could be explained by the calculated oxidation of SO2 by OH. However, the amount of volume growth varied substantially from day to day, even in the plume of the same power plant. In the only case in which a quantitative growth law analysis could be performed, the observed growth of particle size with increasing plume age was consistent with condensation and inconsistent with aqueous oxidation. The advected particle volume flux in SO2-rich power plant plumes substantially exceeded that measured in the urban plumes downwind of Nashville and Atlanta.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2001JD001062

Particle growth in the plumes of coal‐fired power plants

The UV absorption cross-sections of methyl, ethyl and
isopropyl nitrate between 233 and 340 nm have been measured
using a diode array spectrometer in the temperature range
240–360 K. The absorption cross-sections of these
alkyl nitrates decrease with increasing wavelength and
decrease with decreasing temperature for λ>280 nm.
The photodissociation quantum yield for
CH
 3
ONO
 2
 to produce NO
 2
 and
CH
 3
O was found to be essentially unity at 248 nm
using transient UV absorption methods. Production of O and H
atoms in the photodissociation of methyl nitrate at 248 and
308 nm were found to be negligible using resonance
fluorescence detection of the atoms. High quantum yields for
O atoms were measured following 193 nm photolysis of methyl
nitrate. The OH radical was measured to be a photoproduct
with a very small quantum yield. Using the OH rate
coefficients reported in the accompanying paper and the UV
absorption cross-sections and the photodissociation quantum
yields measured here, the first-order rate constants for
atmospheric loss of methyl, ethyl and isopropyl nitrate were
calculated. Photolysis was found to be the dominant
atmospheric loss process for the three alkyl nitrates.

Atmospheric fate of several alkyl nitrates Part2UV absorption cross-sectionsand photodissociation quantum yields

On reporte 58 coefficients de vitesse bimoleculaire dans diverses conditions de temperature (260-420 K) et de pression, avec M=He, Ar, N 2 , SF 6

Kinetics of the reaction OH + SO2 + M .fwdarw. HOSO2 + M. Temperature and pressure dependence in the fall-off region

The quantum yield for the production of NO3 in the N2O5 photolysis at 248 nm was measured to be unity. The concentration of NO3 produced upon photolysis was measured using 662-nm laser absorption. The quantum yields for O(3P) production in the photolysis of N2O5 at 248 nm, 266 nm, 287 nm, and 289 nm were also measured using resonance fluorescence detection of O(3P). The quantum yield for O(3P) decreased from 0.7 at 248 nm to 0.15 at 289 nm. It is postulated that N2O5 photolysis at wavelengths less than 298 nm yields NO3 + NO + O(3P)in addition to NO3 + NO2.

A. Torabi

Papers

Kinetics of the reaction OH + SO2 + M .fwdarw. HOSO2 + M. Temperature and pressure dependence in the fall-off region

N2O5 photolysis: Quantum yields for NO3 and O(3 P)

Kinetics of the reaction oh + so2 + m → hoso2 + m. temperature and pressure dependence in the fall-off region