HIGH-RESOLUTION SPECTRA OF CH2OO : ASSIGNMENTS OF _5 AND 2_9 BANDS AND OVERLAPPED BANDS OF ICH2OO

Huang, Yu-Hsuan

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Description

Title

HIGH-RESOLUTION SPECTRA OF CH2OO : ASSIGNMENTS OF _5 AND 2_9 BANDS AND OVERLAPPED BANDS OF ICH2OO

Author(s)

Huang, Yu-Hsuan

Contributor(s)

• Lee, Yuan-Pern
• Chen, Li-Wei

Issue Date

26-Jun-15

Keyword(s)

Atmospheric science

Abstract

The simplest Criegee intermediate chem{CH_2OO}, important in atmospheric chemistry, has recently been detected with infrared (IR) absorption in the reaction of chem{CH_2I} + chem{O_2}.footnote {Y.-T. ~Su, Y.-H. ~Huang, H. A. ~Witek, and Y.-P. ~Lee, Science {bf340}, 174 (2013).} We have recorded high-resolution infrared spectrum of chem{CH_2OO} with rotational lines partially resolved. In additional to derivation of some critical spectral parameters to confirm the previous assignments of $nu$$_{3}$ at 1434.1 cm$^{-1}$, $nu$$_{4}$ at 1285.7 cm$^{-1}$, $nu$$_{6}$ at 909.2 cm$^{-1}$, and $nu$$_{8}$ at 847.4 cm$^{-1}$, the high-resolution spectra enable us to assign with confidence the 2$nu$$_{9}$ at 1233.5 cm$^{-1}$ and $nu$$_{5}$ at 1213.0 cm$^{-1}$. Observed vibrational wavenumbers, relative intensities, and rotational structures agree well with those predicted by high-level quantum calculations. Some additional hot bands and combination bands are also observed. We also recorded the IR spectrum of chem{ICH_2OO} under high-pressure conditions. Observed IR intensities and vibrational wavenumbers of 1233.8 ($nu$$_{4}$), 1221 ($nu$$_{5}$), 1087 ($nu$$_{6}$), and 923 ($nu$$_{7}$) cm$^{-1}$ agree with those simulated according to theoretical predictions and those observed in solid ${p}$-chem{H_2}.footnote {Y.-F. ~Lee and Y.-P. ~Lee, Chem. Phys. DOI: 10.1080/00268976.2015.1012129} The $nu$$_{4}$ band of chem{ICH_2OO} interferes with the 2$nu$$_{9}$ band of chem{CH_2OO} even at pressure as low as 100 Torr. With direct detection of both chem{CH_2OO} and chem{ICH_2OO}, we determined the pressure dependence of the yield of chem{CH_2OO}. The yield of chem{CH_2OO} near one atmosphere is greater than previous reports.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

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