Intracavity laser spectroscopy of high-temperature water vapour in the range 9390–9450 cm⁻¹

Abstract

The absorption spectra of water vapour were studied in the range 9390–9450 cm⁻¹ using an ICL-spectrometer based on a Nd-glass laser with a spectral resolution of 0.036 cm⁻¹ and threshold sensitivity to absorption of 10⁻⁸ cm⁻¹. A high temperature absorption cell was used to record the H₂O spectra at temperatures of 300 to 800 K and a Multyplaz-2500 plasma source enabled water vapour temperatures up to 3000 K. The recorded spectra are very dense over the wavenumber region investigated, showing in addition to the water lines, absorption of the OH molecule. More than 250 absorption lines were detected in the high-temperature spectra of water vapour. Lines determined by transitions to the second hexade of H₂O from the ground vibration state as well as hot bands were assigned. The temperature of the flame and the concentration of the OH molecules were also determined using the OH transitions in the ground electronic state.

Acknowledgements

This work was partly supported by the Russian Foundation for Basic Research (Grants No. 05-03-32782, 05-05-22001) and by INTAS Grant. N 03-51-3394.