High resolution quantum cascade laser spectroscopy of the simplest Criegee intermediate, CH2OO, between 1273 cm−1 and 1290 cm−1

Abstract

The region 1273-1290 cm

Temperature‐dependent kinetics of the simplest Criegee intermediate reaction with dimethyl sulfoxide

“…The detailed rotational fine structure of this vibrational band has been published. [25] The observed spectra in Figure 2 show characteristic structures of transitions from K quantum numbers of 3 to 8, consistent with the reported spectra. [25] This distinct spectral feature offers a definitive identification of CH 2 OO.…”

“…[25] The observed spectra in Figure 2 show characteristic structures of transitions from K quantum numbers of 3 to 8, consistent with the reported spectra. [25] This distinct spectral feature offers a definitive identification of CH 2 OO. At the selected photolysis-probe delay time (0.5 ms), the signal of CH 2 OO decreases at higher [DMSO], indicating the reaction of CH 2 OO with DMSO.…”

“…Here the main decay pathways are the wall loss and CH 2 OO reactions with radical species, including I atoms, CH 2 OO, etc. [ 25–27 ] The used [CH 2 OO] 0 was on the order of 10 12 cm −3 . Under such conditions, the effect CH 2 OO self‐reaction [ 28 ] is minor in the kinetics of CH 2 OO reaction with DMSO.…”

“…The delay time (between the photolysis and probe laser pulses) of these spectra is 0.5 ms. The spectral feature corresponds to the Q branch of ν 4 fundamental transition of CH 2 OO and the sub-bands have been assigned to K = 3-8 as labeled on the figure, which has been reported by Chang et al [25] The absorption signal between 1,285.67 and 1,285.93 cm −1 (marked as two dash-dotted lines) was averaged for each probe pulse to obtain a time profile, like the one in…”

“…The experimental setup was similar to those described previously. [25][26][27] We followed the well-established method reported by Welz et al to prepare CH 2 OO (CH 2 I 2 + hν ! CH 2 I + I; CH 2 I + O 2 !…”