MULTISPECTRAL FITTING VALIDATION OF THE SPEED DEPENDENT VOIGT PROFILE AT UP TO 1300K IN WATER VAPOR WITH A DUAL FREQUENCY COMB SPECTROMETER

Using broadband, high resolution dual frequency comb spectroscopy, we test the power law temperature scaling relationship with Voigt, Rautian, and quadratic speed dependent Voigt profiles over a temperature range of 296-1300K for pure water vapor. The instrument covers the spectral range from 6800 cm$^{-1}$ to 7200 cm$^{-1}$ and samples the (101)-(000), (200)-(000), (021)-(000), (111)-(010), (210)-(010), and (031)-(010) vibrational bands of water. The data is sampled with a point spacing of 0.0033 cm$^{-1}$ and absolute frequency accuracy of $<$3.34e-6 cm$^{-1}$. This region is of interest for detection and quantification of hot water and gas temperature within coal gasifiers and other high temperature systems. In order to extract water concentration and temperature, an extended range of lineshape parameters are needed. Lineshape parameters for pure and argon broadened water are obtained for 278 transitions using the multispectral fitting program Labfit, including self-broadening coefficients, power law temperature scaling exponents, and speed dependence coefficients. The extended temperature range of the data provides valuable insight into the application of the speed-dependence corrections of the line profiles, which are shown to have more reasonable line broadening temperature dependencies