Atmospheric chemistry of diazomethane - an experimental and theoretical study

The kinetics of the O-3, OH and NO3 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) x 10(-17) and k(CH2NN+OH) = (1.68 +/- 0.12) x 10(-10) cm(3) molecule(-1) s(-1) at 295 +/- 3 K and 1013 +/- 30 hPa, whereas the CH2NN + NO3 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.