An accurate and complete empirical line list for water vapor between 5850 and 7920 cm−1

Abstract

An empirical line list has been constructed for “natural” water vapor at 296K in the 5850–7920cm−1 region. It was obtained by gathering separate line lists recently published on the basis of spectra recorded by high sensitivity Continuous Wave Cavity Ring Down Spectroscopy (CW-CRDS) of natural water, complemented with literature data for the strongest lines. The list includes 38,318 transitions of four major water isotopologues (H216O, H218O, H217O and HD16O) with an intensity cut-off of 1×10−29cm/molecule at 296K. The list is made mostly complete over the whole spectral region by including a large number of weak lines with positions calculated using experimentally determined energy levels and intensities obtained from variational calculations. In addition, we provide HD18O and HD17O lists in the same region for transitions with intensities larger than 1×10−29cm/molecule. The HD18O and HD17O lists (1972 lines in total) were obtained using empirical energy levels available in the literature and variational intensities.The global list (40,290 transitions) for water including the contribution of the six major isotopologues will be adopted for the next edition of the GEISA database in the region.The advantages and drawbacks of our list are discussed in comparison with the list provided for the same region in the 2012 edition of the HITRAN database. The direct comparison of the CRDS spectra to simulations based on the HITRAN list has revealed some insufficiencies which could easily be corrected: missing HDO lines, duplicated lines, inaccurate line positions or line intensities from variational calculations.