We present measurements of absorption spectra of hot-water vapor generated in a propane–air flame in the far-infrared region of the spectrum from 0.1 to 3.5 THz (3.3 to 117cm<sup>-1</sup>). Transitions within the rotational manifold of both the ground and the ν<sub>2</sub>=1 vibrational levels were observed. The measurements are in good agreement with calculations of the predicted absorption spectra at 1300 K based on tabulated line intensities, whereas predicted theoretical line widths were found to be approximately one third too narrow.
© 1998 Optical Society of America
R. Alan Cheville and D. Grischkowsky, "Observation of pure rotational absorption spectra in the ν2 band of hot H2O in flames," Opt. Lett. 23, 531-533 (1998)