High-resolution infrared spectroscopy slit-jet cooled hydroxymethyl radical(CH2OH): CH symmetric stretching mode

Wang, Fang

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https://hdl.handle.net/2142/50878 Copy

Description

Title

High-resolution infrared spectroscopy slit-jet cooled hydroxymethyl radical(CH2OH): CH symmetric stretching mode

Author(s)

Wang, Fang

Contributor(s)

• Nesbitt, David
• Chang, Chih-Hsuan

Issue Date

2014-06-17

Keyword(s)

Structure determination

Abstract

"Hydroxymethyl radical (CH$_2$OH) plays an important role in combustion and environmental chemistry as a reactive intermediate. Reisler's group published\footnote{L. Feng, J. Wei and H. Reisler, J. Phys. Chem. A, Vol. 108.} the first rotationally resolved spectroscopy of CH$_2$OH with determined band origins for fundamental CH symmetric stretch state, CH asymmetric stretch state and OH stretch state, respectively. Here CH$_2$OH was first studied via sub-Doppler infrared spectroscopy in a slit-jet supersonic discharge expansion source. Rotationally resolved direct absorption spectra in the CH symmetric stretching mode were recorded. As a result of the low rotational temperature and sub-Doppler linewidths, the tunneling splittings due to the large amplitude of COH torsion slightly complicate the spectra. Each of the ground vibration state and the CH symmetric stretch state includes two levels. One level, with a 3:1 nuclear spin statistic ratio for \textit{K$_{a}$}=0$^{+}$/\textit{K$_{a}$}=1$^{+}$, is labeled as ``+"". The other tunneling level, labeled as ``-"", has \textit{K$_{a}$}=0$^{-}$/\textit{K$_{a}$}=1$^{-}$ states with 1:3 nuclear spin statistics. Except for the \textit{K$_{a}$}=0$^{+}$ $\leftarrow$ 0$^{+}$ band published before \footnote{M. A. Roberts, E. N. Sharp-Williams and D. J. Nesbitt, J. Phys. Chem. A 2013, 117, 7042-7049}, more bands (\textit{K$_{a}$}=1$^{+}$ $\leftarrow$ 1$^{+}$ , \textit{K$_{a}$}=0$^{-}$ $\leftarrow$ 0$^{-}$ and \textit{K$_{a}$}=1$^{-}$ $\leftarrow$ 1$^{-}$) were identified. The assigned transitions were fit to a Watson A-reduced symmetric top Hamiltonian to improve the accuracy of the band origin of CH symmetric state. The rotational parameters for both ground and CH symmetric stretch state were well determined."

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/50878

DOI

https://doi.org/10.15278/isms.2014.TE01

Copyright and License Information

Copyright 2014 by the authors. Licensed under a Creative Commons Attribution 4.0 International License. http://creativecommons.org/licenses/by/4.0/

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