Water vapor absorption spectroscopy and validation tests of databases in the far-infrared (50–720 cm−1). Part 2: H217O and HD17O

Abstract

The present work is the second part of our systematic study of the absorption spectrum of the water vapor isotopologues by high resolution (≈ 0.001 cm−1) Fourier transform spectroscopy in the far infrared (50–721 cm−1). The room temperature spectra were recorded at the AILES beam line of the SOLEIL synchrotron with an absorption pathlength of 151.75 m. Here, we consider three spectra of a water vapor sample highly enriched in 17O. Line parameters retrieved from the three spectra were combined in a global list of 4432 water lines (assigned to 4651 transitions). The spectral calibration based on a statistical matching with about 370 accurate reference line positions of H216O allows for line center determinations with an accuracy of 5×10−5 cm−1 for well isolated lines of intermediate intensity. Six water isotopologues (H218O, H216O, H217O, HD18O, HD16O, and HD17O) were found to contribute to the spectrum. 460 and 99 of the measured H217O and HD17O transitions are newly observed by absorption spectroscopy. 69 H217O and 20 HD17O energy values of the ground (000) and first excited (010) states are newly determined.The present set of measured H217O line positions is combined with 24 literature sources to provide a list of 821 empirical energies for the first five vibrational states – (000), (010), (020), (100), and (001) – using the RITZ principle. A set of 332 rotational energies of the (000) and (010) states of HD17O is determined by merging the 465 HD17O transitions measured in the present study to eight literature sources.