LED-based Fourier transform spectroscopy of H218O in the 15,000-16,000 cm−1 range

- The spectrum of H218O was studied between 15,000 and 16,000 cm−1 for the first time.
- 426 Levels of 11 states of H218O were determined.
- 72 Levels of 6 states of H217O were determined for the first time.

The spectrum of Н218О has been recorded between 15,000 and 16,000 cm−1 by a Fourier transform spectrometer with spectral resolutions of 0.03 cm−1 and 0.05 cm−1 using high luminance LED light sources and a 60-cm multipath cell with a path length of 1920 and 3480 cm. A high signal-to-noise ratio (S/N=10,000) enabled us to register more than 1500 water vapor lines with intensities 1.0×10-27 to 2.2×10−24 cm/molecule at 296 K. 426 rotational-vibrational levels of the H218O molecule were assigned to eleven vibrational states: (014), (033), (052), (113), (132), (151), (212), (231), (311), (330) and (410). 72 Rotational-vibrational levels of the H217O molecule were assigned to six vibrational states: (014), (033), (113), (212), (311) and (410). An extended set of H218O transitions in the 15,000-16,000 cm−1 range was generated using the obtained energy level list and the results of a variational intensity calculation.