# FOURIER TRANSFORM RAMAN SPECTROSCOPY OF $H_{2}$ AND $D_{2}$ IN FLAMES

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 Title: FOURIER TRANSFORM RAMAN SPECTROSCOPY OF $H_{2}$ AND $D_{2}$ IN FLAMES Creators: Jennings, D. E.; Weber, A.; Brault, J. W. Issue Date: 1985 Abstract: Laboratory spectra of high rotational transitions in $H_{2}$ are important in astrophysics because they may be observable in hot stellar and interstellar sources, and have already been seen in quadrupole emission from the Orion molecular $cloud.^{1}$ The Orion emission lines are characteristic of an $\sim$ 2000K rotational temperature. Infrared spectra of $H_{2}$ and $D_{2}$ at high temperatures are difficult to obtain in the laboratory because path lengths of hundreds of meters are necessary to observe the quadrupole absorption. Vibration-rotation coefficients obtained from room temperature spectra cannot be extrapolated to the high-J lines observed in Orion to within the accuracies of the astronomical measurements. Prompted by these considerations, we have recorded Raman spectra of high temperature molecular hydrogen and deuterium using a Fourier transform spectrometer. A diffusion flame source burning $H_{2}$ or $D_{2}$ in air was placed at the focal point of a multi-pass $cell.^{2}$ Raman scattering of argon-ion laser light was observed with the l-m Fourier transform spectrometer at Kitt $Peak.^{3}$ The observed pure-rotation spectra of $H_{2}$ and $D_{2}$, and the vibration-rotation spectra of $H_{2}$, contain transitions with higher rotational energy than had been possible to observe previously at room temperature. The transitions in $H_{2}$ extended to J=9-7 and those in $D_{2}$ extended to J=12-10. The rotation-vibration coefficients will be re-examined taking the new transitions into account. URI: http://hdl.handle.net/1811/12292 Other Identifiers: 1985-WF-6