Atmospheric chemistry of diazomethane - an experimental and theoretical study

The kinetics of the O 3 , OH and NO 3 radical reactions with diazomethane were studied in smog chamber experiments employing long-path FTIR and PTR-ToF-MS detection. The rate coefficients were determined to be k CH2NN+O3 = (3.2 ± 0.4) × 10 −17 and k CH2NN+OH = (1.68 ± 0.12) × 10 −10 cm 3 molecule −1 s −1 at 295 ± 3 K and 1013 ± 30 hPa, whereas the CH 2 NN + NO 3 reaction was too fast to be determined in the static smog chamber experiments. Formaldehyde was the sole product observed in all the reactions. The experimental results are supported by CCSD(T*)-F12a/aug-cc-pVTZ//M062X/aug-cc-pVTZ calculations showing the reactions to proceed exclusively via addition to the carbon atom. The atmospheric fate of diazomethane is discussed.