International Comparison CCQM-P229: Pilot Study to Measure Absolute Line Intensities of Selected 12C16O Transitions

Published

January 24, 2025

Author(s)

Joseph Hodges, Zachary Reed, Katarzyna Bielska, Manfred Birk, Ruimin Guo, Gang Li, Jeong Sik Lim, Daniel Lisak, Georg Wagner

Abstract

We present primary spectroscopic measurements of line intensities in the 3-0 vibrational band of 12C16O. This international measurement campaign was organized under the auspices of the Consultative Committee for Amount of Substance (CCQM) and involved six laboratories carrying out independent measurements of more than forty rotation-vibration transitions. A total of three measurement techniques on samples of pure carbon monoxide were applied in this intercomparison, including Fourier transform spectroscopy, cavity ring-down spectroscopy, and cavity mode dispersion spectroscopy. Using advanced spectroscopic line shape models and thorough characterization of instrument response to analyze the measured spectra, artifact-free measurements of line intensities were obtained by each laboratory., The final results were weighted by the inverse of the combined variance determined from rigorous estimates of combined systematic and statistical uncertainties. Results for all lines from five of the laboratories were scattered about the weighted mean value by nominally one part per thousand. Comparison of the weighted integrated band intensity with quantum-chemical calculations differed by 0.13 parts per thousand, thus demonstrating excellent agreement between experiment and theory. These results serve as an experimental benchmark for assessing the uncertainty in theoretical calculations, and they reveal the benefits of coordinated experiments that leverage complementary and independent primary measurements from contributing laboratories.

Citation

Metrologia

Pub Type

Journals

Keywords

line intensity:, Carbon Monoxide, International Comparison, Absorption Spectroscopy

Citation

Hodges, J. , Reed, Z. , Bielska, K. , Birk, M. , Guo, R. , Li, G. , Lim, J. , Lisak, D. and Wagner, G. (2025), International Comparison CCQM-P229: Pilot Study to Measure Absolute Line Intensities of Selected 12C16O Transitions, Metrologia (Accessed April 11, 2025)