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Title:EXPLORATIONS OF INFRARED SPECTRA OF CRIEGEE INTERMEDIATES AND THEIR REACTIONS
Author(s):Lee, Yuan-Pern
Subject(s):Plenary
Abstract:Criegee intermediates, carbonyl oxides produced in ozonolysis of unsaturated hydrocarbons, play important roles in atmospheric chemistry. A new production scheme using photolysis of R$_{2}$CI$_{2}$ + O$_{2}$ facilitated the production and direct detection of Criegee intermediates with various spectral techniques and has stimulated rapidly expanding research.\footnote {Y.-P. ~Lee, \textit{J. Chem. Phys.} \underline{\textbf{143}}, 020901 (2015).}$^{,}$\footnote {D. L. ~Osborn, C. A. ~Taatjes, \textit{Int. Rev. Phys. Chem.} \underline{\textbf{34}}, 309 (2015).} Our understanding of important atmospheric reactions involving Criegee intermediates is becoming clarified because of the direct probing of Criegee intermediates in kinetic experiments. The infrared spectra of CH$_{2}$OO,\footnote { Y. T. ~Su, Y.-H. ~Huang, H. A. ~Witek, Y.-P. ~Lee, \textit{Science} \underline{\textbf{340}}, 174 (2013).}$^{,}$\footnote {Y.-H. ~Huang, J. ~Li, H. ~Guo, Y.-P. ~Lee, \textit{J. Chem. Phys.} \underline{\textbf{142}}, 214301 (2015).} CH$_{3}$CHOO,\footnote {H.-Y. ~Lin, Y.-H. ~Huang, X. ~Wang, J. M. ~Bowman, Y. ~Nishimura, H. A. ~Witek, Y.-P. ~Lee, \textit{Nature Comm.} \underline{\textbf{6}}, 7012 (2015).} and (CH3)$_{2}$COO\footnote {Y.-Y. ~Wang, C.-Y. ~Chung, Y.-P. ~Lee, \textit{J. Chem. Phys.} \underline{\textbf{145}}, 154303 (2016).} have been recorded with a step-scan FTIR with resolution 0.25 to 1 cm$^{-1}$; rotational contours with unresolved rotational lines were reported. On employing a quantum cascade laser coupled with a Herriot cell, we recorded spectra of the O-O stretching bands of CH$_{2}$OO and CH$_{3}$CHOO in the region 880-932 cm$^{-1}$ at resolution 0.002 cm$^{-1}$. In addition to improved rotational parameters, perturbation was observed at high-\textit{J} levels of \textit{K}$_{a}$ = 3, 6, and 11 of CH$_{2}$OO. Distinct lines of \textit{syn}- and \textit{anti}-CH$_{3}$CHOO were also observed. Kinetic investigations based on this new experimental scheme will be presented. Taking advantage of the wide spectral coverage of an FTIR, we investigated the mechanism of the reactions of CH$_{2}$OO with SO$_{2}$, HNO$_{3}$, HCl, and HCOOH. For example, in the reaction of CH$_{2}$OO + HCOOH, eight observed bands are assigned to hydroperoxymethyl formate HPMF (P5). In the later reaction period, three bands are assigned to an isomer HPMF (P6) and three bands to the final product, \textit{anti}-FAN. According to our kinetic analysis, only P5, not P6, decomposes to form FAN.
Issue Date:06/18/18
Publisher:International Symposium on Molecular Spectroscopy
Citation Info:APS
Genre:Conference Paper / Presentation
Type:Text
Language:English
URI:http://hdl.handle.net/2142/100686
DOI:10.15278/isms.2018.MA04
Other Identifier(s):MA04
Date Available in IDEALS:2018-08-17
2018-12-12


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