Observations of Dicke narrowing and speed dependence in air-broadened CO2 lineshape near 2.06 um

Published

November 3, 2014

Author(s)

Thinh Q. Bui, David Long, Agata Cygan, Vincent T. Sironneau, Daniel Hogan, Priyanka M. Rapusinghe, Mitchio Okumura

Abstract

Frequency-stabilized cavity ring-down spectroscopy (FS-CRDS) was used to study CO2 lineshapes in the (20013)←(00001) band centered near 2.06 um. Two rovibrational transitions were chosen for this study to measure non-Voigt collisional effects for air-broadened lines over the pressure range of 7-27 kPa. Lineshape analysis for both lines revealed evidence of simultaneous Dicke (collisional) narrowing and speed-dependent effects, which if not incorporated in the modeling of CO2 lineshapes, introduces biases exceeding 5% in the retrieved air-broadening parameters. As a result, it was observed that the most appropriate line profile for modeling CO2 lineshapes near 2.06 um was the speed-dependent Nelkin-Ghatak profile, which includes both collisional narrowing and speed-dependent effects.

Citation

Journal of Chemical Physics

Volume

141

Pub Type

Journals

Download Paper

DOI Link

Keywords

Carbon dioxide, Cavity ring-down spectroscopy, Line shapes, Line profiles, Remote sensing

Citation

Bui, T. , Long, D. , Cygan, A. , Sironneau, V. , Hogan, D. , Rapusinghe, P. and Okumura, M. (2014), Observations of Dicke narrowing and speed dependence in air-broadened CO2 lineshape near 2.06 um, Journal of Chemical Physics, [online], https://doi.org/10.1063/1.4900502 (Accessed October 10, 2025)