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

Wang, Fang

Permalink

https://hdl.handle.net/2142/50881 Copy

Description

Title

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

Author(s)

Wang, Fang

Contributor(s)

• Nesbitt, David
• Chang, Chih-Hsuan

Issue Date

2014-06-17

Keyword(s)

Atmospheric science

Abstract

"Rotationally resolved direct absorption spectra in the OH stretching mode were recorded using difference frequency generation infrared spectrometer and slit-jet supersonic discharge expansion source. The spectra are really complicated because of the following reasons: a) CH$_2$OH was generated by discharging the expansion mixed gas CH$_3$OH and Cl$_2$ in carrier gas 70\% Ne and 30\% He. Large signals for CH$_3$OH are overlapped with that for CH$_2$OH in the OH stretching mode. b) The large amplitude of COH torsion for CH$_2$OH splits each vibration state into two states labeled as ``+"" and ``-"". The ``+"" state has energy levels with a 3:1 nuclear spin statistic ratio for \textit{K$_a$}=0$^+$/\textit{K$_a$}=1$^+$. The ``-"" state has \textit{K$_a$}=0$^-$/\textit{K$_a$}=1$^-$ levels with 1:3 nuclear spin statistics. c) The OH stretch fundamental is a hybrid \textit{a/b}-type band. Both \textit{a}-type and \textit{b}-type bands were observed. As a result of the low rotational temperature and sub-Doppler linewiths, the spin-rotation structure was also resolved for \textit{b}-type transitions. The spectra were assigned and fit to a Watson A-reduced symmetric top Hamiltonian to improve the accuracy of rotational parameters for the ground vibration state and determine the rotational parameters for the OH stretch state. The spin rotational constants and the tunneling splittings for both ground and OH stretch state were also determined."

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/50881

DOI

https://doi.org/10.15278/isms.2014.TI03

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/

Owning Collections