Temperature Dependence of the Chemiluminescent Reaction (1), NO + O₃ → NO₂(²A₁; ²B_1,2) + O₂, and Quenching of the Excited Product

Abstract

The title reaction (1) was studied at very low total pressures. The activation energy of the chemiluminescent pathway (1a) depends on the wavelength range in which emission is detected. Measurements at 1.27 μ, close to the maximum of the emission spectrum, yield 16.2 kJ mol−1 which presumably equals the activation energy E1a of the chemiluminescence integrated over all wavelengths. The absolute quantum yield at 290 K was determined to be k1a/k1 = 0.20, using the infrared atmospheric band emitted by known concentrations of O2(1Δg) as intensity standard. These results are combined with temperature dependent rate constants of the bulk reaction to yield separate Arrhenius equations, k1a = 2.90 · 10−12 exp(‐1951 K/T) cm3 s−1 for the electronically excited product, and k1b = 2.27 · 10−12 exp(‐1475 K/T) cm3 s−1 for the dark component of reaction (1). The half‐quenching densities of the chemiluminescence were found to be both wavelength‐ and temperature dependent, following approximately a T0.5 dependence for M = N2.

Shock Wave Induced Decomposition of RDX: Time-Resolved Spectroscopy

“…The NO 2 radical likely plays an important role in RDX decomposition. The luminescence spectrum of excited NO 2 is very broad, almost forming a continuum. – The peak of this continuum emission varies depending on the conditions under which the excited NO 2 was produced, and can vary from the visible (500−600 nm) – to the near-infrared (1200 nm). ,,,, Because of the differences in the experimental conditions, our results are not directly comparable to these other studies. Temperature and pressure effects likely change the emission spectrum of NO 2 .…”

Kinetics of the OH + NO2 reaction: Rate coefficients (217–333 K, 16–1200 mbar) and fall-off parameters for N2 and O2 bath-gases

“…For these reasons, we checked the validity and the magnitude of the correction that needed to be applied to (Keil et al, 1980). Only Schurath et al (Schurath et al, 1981) report a weak negative T-dependence (T -0.42 ) on the fluorescence quenching rate constant for NO2* (formed in the NO + O3 reaction) in N2 between 285 and 446 K, but acknowledge that the T-dependence might be erroneous due to the large scatter in their dataset.…”

Prototype for In Situ Detection of Atmospheric NO3 and N2O5 via Laser-Induced Fluorescence

“…The ratio of excitation rates E NO 3 / E NO 2 (eq 3) is 400 due to the higher absorption cross section of NO 3 at 662 nm as compared to that of NO 2 at 585 nm. The product ( T × ε) is much lower for NO 2 than for NO 3 as most of NO 2 fluorescence occurs in the near-IR ( , ) and therefore outside the active spectral region of efficient red-sensitive photomultiplier tubes, whereas NO 3 fluoresces almost entirely in the visible. We estimate that only ∼8% of the full spectral range of NO 2 fluorescence is collected within the spectral window of our NO 2 instrument (700−850 nm), whereas 50% of NO 3 fluorescence is collected within a spectral window of 700−750 nm for an NO 3 instrument.…”