Improved assessment of H216O transitions in the region 6600–7500 cm−1

Due to the very large number of experimental, empirical, and computational studies addressing the rovibrational transitions and the underlying energy levels of the main isotopologue, H${}_2^{16}$O, of the water molecule, the room-temperature coverage offered by the canonical line-by-line spectroscopic database HITRAN2020 is almost complete, 99.87%, up to 6600 cm${}^{-1}$. This study provides a detailed comparison of two recent datasets, one with measured line positions and intensities, obtained using a dual-comb spectrometer (DCS), from 6600 to 7500 cm${}^{-1}$ at temperatures up to 1300 K (neglecting the experimentally covered region of 7500–7650 cm${}^{-1}$ with noisy spectral features), and the other a composite empirical line list, called CW2024, covering the spectrum from the microwave to the ultraviolet. The aim has been the mutual validation of the two datasets, correction of possible errors in both of them, and providing additional validated experimental data for inclusion in line-by-line databases. At the end, 5419 transitions from the DCS measurement database were investigated with respect to those in the CW2024 line list, with the majority of the lines falling within the respective individual uncertainties of the two datasets. Using the composite empirical CW2024 database as a reference, 423 assignments were made for a subset of the 616 lines measured at high temperatures which are not part of HITRAN2020. Thus, in the region 6600–7500 cm${}^{-1}$ all but seven transitions, with intensities above a room-temperature cutoff of $1\times 10^{-28}$ cm molecule⁻¹, have become experimentally known. In the Supplementary Material to this paper, an updated DCS database is provided, showcasing the improvements described in the article.