High-resolution Laser Spectroscopy Of The S1 ← S0 Transition Of Acetaldehyde

Kasahara, Shunji

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https://hdl.handle.net/2142/116920 Copy

Description

Title

High-resolution Laser Spectroscopy Of The S1 ← S0 Transition Of Acetaldehyde

Author(s)

Kasahara, Shunji

Contributor(s)

• Baba, Masaaki
• Taniguchi, Rin
• Shimizu, Akira
• Nakajima, Kosuke

Issue Date

2022-06-22

Keyword(s)

Large amplitude motions, internal rotation

Abstract

Acetaldehyde is one of a prototype molecule to study large amplitude motion. In the ground state, the energy level structure were well understood by considering the methyl torsional motion ($\nu_{15}$ mode). \footnote{I. Kleiner, J. T. Hougen, J. -U. Grabow, M. Mckhtiev, and J. Cosleou, {\em J. Mol. Spectrosc.}, {\bf 179}, 41 (1996).} On the other hand, in the $S_{1}$ state, it is necessary to consider the aldehyde-hydrogen inversion mortion ($\nu_{14}$ mode) \footnote{M. Baba, I. Hanazaki, U. Nagashima, {\em J. Chem. Phys.}, {\bf 82}, 3938 (1985).} \footnote{M. Nobleand K. C. Lee, {\em J. Chem. Phys.}, {\bf 81}, 1632 (1984).} in addition to the methyl torsion. Rotationally-resolved spectrum of the $S_{1} \leftarrow S_{0}$ transition were observed by using a pulsed amplified CW laser, and obtained effective rotational constants. \footnote{Y.-C. Chou, C.-L. Huang, I-C. Chen, C.-K. Ni, A. H. Kung, {\em J. Chem Phys.}, {\bf 115}, 5089 (2001).} \footnote{H. Liu, E. C. Lim, A. Nino, C. Munoz-Caro, R. H. Judge, D. C. Moule, {\em J. Mol. Spectrosc.}, {\bf 190}, 78 (1998).} In this work, rotationally-resolved high-resolution fluorescence excitation spectra of the $S_{1} \leftarrow S_{0}$ transition of acetaldehyde have been observed. Sub-Doppler excitation spectra were measured by crossing a single-mode UV laser beam perpendicular to a collimated molecular beam. The typical linewidth of observed spectra was about 40 MHz. The absolute wavenumber was calibrated with accuracy 0.0002 cm$^{-1}$ by measurement of the Doppler-free saturation spectrum of iodine molecule and fringe pattern of the stabilized etalon. The observed spectra around 30118 cm$^{-1}$ and 30375 cm$^{-1}$ correspond to $14^{0-}_0 15^2_0$ and $14^{0+}_0 15^4_0$ band, respectively. We are trying to analyze the rotational structure including the interaction with the large amplitude motions and then determine the parameters of the $S_{1}$ state.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Genre of Resource

Conference Paper / Presentation

Language

eng

Handle URL

https://hdl.handle.net/2142/116920

DOI

https://doi.org/10.15278/isms.2022.WF10

Copyright and License Information

Copyright 2022 held by the authors

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