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<sup>-1</sup> was selected to avoid degrading sharp spec- tral features, while also realizing that atmospheric broadening typ- ically limits line widths to 0.1 cm<sup>-1</sup>. Calculated positional (wave- number, cm<sup>-1</sup>) uncertainty is ≤0.005 cm<sup>-1</sup>, 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.

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