Atmospheric chemistry of diazomethane – an experimental and theoretical study

Figures & data

Figure 1. Normalised counts per second of the m/z 43.028 ion signal (CH₃N₂⁺) as a function of time during a CH₂NN + O₃ experiment. Full red curve: modelled CH₂N₂ decay. Dotted red curve: extrapolated model results. Inserted plot shows the O₃ decay during the experiment.

Figure 2. (A) Decays of diazomethane, limonene and α-pinene in the presence of OH radicals in 1 of the 2 experiments carried out. The data have been plotted as ln{[Diazomethane]₀/[Diazomethane]_t} vs. respectively ln{[Limonene]₀/[Limone]_t} or ln{[α-Pinene]₀/[α-Pinene]_t}. Analysis of the data points shown give relative rate coefficients k_{Diazomethane+OH}/k_Limonene+OH= 0.9941 ± 0.0017 and k_{Diazomethane+OH}/k_α-Pinene+OH= 3.012 ± 0.006 (1σ). The α-pinene data have been shifted for the sake of clarity.

Figure 3. Stationary points on the potential energy surface of the CH₂NN + OH reaction. Results from CCSD(T*)-F12a/aug-cc-pVTZ//M06-2X/aug-cc-pVTZ calculations.

Figure 4. Stationary points on the potential energy surface of the CH₂NN + NO₃ reaction. Results from CCSD(T*)-F12a/aug-cc-pVTZ//M06-2X/aug-cc-pVTZ calculations. The grey box illustrates the inherent uncertainty in the electronic energy of the NO₃ radical.