High-accuracy 12C16O2 line intensities in the 2 μm wavelength region measured by frequency-stabilized cavity ring-down spectroscopy

J Quant Spectrosc Radiat Transf. 2018 Feb:206:367-377. doi: 10.1016/j.jqsrt.2017.12.008. Epub 2017 Dec 13.

Abstract

Reported here are highly accurate, experimentally measured ro-vibrational transition intensities for the R-branch of the (20012) - (00001) 12C16O2 band near λ = 2 μm. Measurements were performed by a frequency-stabilized cavity ring-down spectroscopy (FS-CRDS) instrument designed to achieve precision molecular spectroscopy in this important region of the infrared. Through careful control and traceable characterization of CO2 sample conditions, and through high-fidelity measurements spanning several months in time, we achieve relative standard uncertainties for the reported transition intensities between 0.15 % and 0.46 %. Such high accuracy spectroscopy is shown to provide a stringent test of calculated potential energy and ab initio dipole moment surfaces, and therefore transition intensities calculated from first principles.

Keywords: Precision molecular spectroscopy; carbon dioxide; cavity ring-down spectroscopy; dipole moment surfaces; infrared spectroscopy; line lists.