FREQUENCY MEASUREMENTS WITH kHz-ACCURACY OF ¹²CO₂ TRANSITIONS IN THE 2.0 μm REGION

Fleurbaey, Helene

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https://hdl.handle.net/2142/122712 Copy

Description

Title

FREQUENCY MEASUREMENTS WITH kHz-ACCURACY OF ¹²CO₂ TRANSITIONS IN THE 2.0 μm REGION

Author(s)

Fleurbaey, Helene

Contributor(s)

• Mondelain, Didier
• Votava, Ondřej
• Romanini, Daniele
• Kassi, Samir
• Čermák, Peter

Issue Date

2023-06-21

Keyword(s)

Linelists

Abstract

Absolute frequencies of 106 ro-vibrational transitions belonging to the 20012-00001 and 20013-00001 bands of ¹²CO₂ have been measured by saturation spectroscopy. Lamb dips were observed using a cavity ring-down spectrometer linked to an optical frequency comb referenced to a GPS-disciplined Rb oscillator. The feed-forward techniqueᵃ was applied to transfer the coherence of very stable comb emission lines to the laser source of the spectrometer (an external cavity diode laser) via an electro-optic modulator. This setup allows achieving transition frequencies measurements with kHz-level accuracy. The transition frequencies of the two bands are reproduced with a (1σ)-rms of about 1 kHz using the standard expression of the ground and upper energy levels, the ground state constants being constrained to the values reported in Wu et al.ᵇ The 20012 and 20013 vibrational states appear thus to be highly isolated except for a local perturbation of the 20012 state leading to an energy shift of 15 kHz at J’=43. Finally, comparison to transition frequencies reported in the HITRAN2020 database and the literature will be presented and discussed.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

Handle URL

https://hdl.handle.net/2142/122712

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