The National Institute of Standards and Technology (NIST) and the Pacific Northwest National Laboratory (PNNL) are each creating quantitative databases containing the vapor-phase infrared spectra of pure chemicals. The digital databases have been created with both laboratory and remote-sensing applications in mind. A spectral resolution of ≊0.1 cm-1 was selected to avoid degrading sharp spec- tral features, while also realizing that atmospheric broadening typ- ically limits line widths to 0.1 cm-1. Calculated positional (wave- number, cm-1) uncertainty is ≤0.005 cm-1, while the 1σ statistical uncertainty in absorbance values is <2% for most compounds. The latter was achieved by measuring multiple (typically ≥9) path length–concentration burdens and fitting a weighted Beer's law plot to each wavenumber channel. The two databases include different classes of compounds and were compared using 12 samples. Though these 12 samples span a range of polarities, absorption strengths, and vapor pressures, the data agree to within experimental uncertainties with only one exception.
Steven W. Sharpe, Timothy J. Johnson, Robert L. Sams, Pamela M. Chu, George C. Rhoderick, and Patricia A. Johnson, "Gas-Phase Databases for Quantitative Infrared Spectroscopy," Appl. Spectrosc. 58, 1452-1461 (2004)