Updating Ch₄ Spectroscopic Models From 6770-7630 Cm^−1 With Dual Frequency Comb Absorption Spectroscopy Up To 1000 K

Yun, David

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https://hdl.handle.net/2142/111523 Copy

Description

Title

Updating Ch₄ Spectroscopic Models From 6770-7630 Cm⁻¹ With Dual Frequency Comb Absorption Spectroscopy Up To 1000 K

Author(s)

Yun, David

Contributor(s)

• Rieker, Gregory B
• Drouin, Brian
• Coburn, Sean
• Egbert, Scott C
• Sung, Keeyoon
• Malarich, Nathan A

Issue Date

2021-06-23

Keyword(s)

Linelists

Abstract

\begin{wrapfigure}{r}{0pt} \includegraphics[scale=0.5]{ISMS_figure99.eps} \end{wrapfigure} Accurate high-temperature methane spectroscopic models are needed to support the discovery and evaluation of methane in hot exoplanet atmospheres. We present data taken with dual frequency comb absorption spectroscopy with a 0.0067 cm$^{-1}$ frequency point spacing of the methane icosad (6770-7630 cm$^{-1}$) of five temperatures up to 1000 K and three pressures up to 300 torr. A comparison of this data to HITRAN2016, HITEMP2020, and ExoMol reveals a best match with HITRAN2016 at room temperatures. However, there are significant mismatches with all three databases at elevated temperatures. Via a multispectrum fitting routine, we demonstrate that significant improvements can be made between HITRAN2016 high-temperature models and our data by updating several spectroscopic parameters. In particular, we update 4381 lower state energies, add 293 new hot absorption features, and apply band-wide changes to line-positions, self-widths, and temperature-dependence exponents for self-widths and self-shifts.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

Permalink

http://hdl.handle.net/2142/111523

DOI

10.15278/isms.2021.WF09

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