10 mu m ethylene: spectroscopy, intensities and a planetary modeler's atlas

FTS and TDL spectra of ethylene in the 10 mum region have been observed, measured, calibrated, assigned and intensities have been measured. The ultimate goal of this work is the production of a planetary modeler's atlas. A spectrum taken in double-pass configuration at the McMath-Pierce FTS instrument at Kitt Peak National Observatory has been frequency calibrated using CO2 laser bands. Results of a previous analysis (Cauuet et al., J Mol Spectrosc 1990;139:191) have enabled the assignment of the FTS spectrum wherein we have measured over 500 line intensities in the 900-1000 cm(-1) region. These FTS intensities have been calibrated against 13 isolated transitions, taken as secondary intensity standards. These standard lines have been measured independently using TDL (tunable-diode-laser) spectrometers at University of Tennessee and Goddard Space Flight Center. A calculated spectrum, including mixing coefficients for v(4), v(7), v(10) and v(12), and calculated relative intensities, and the TDL-calibrated FTS line intensities were used as data in a non-linear regression analysis to determine the 296 K vibrational band intensities of S-0-7(v) = 321.69 +/- 0.36 cm(-1)/cm atm, S-0-10(v) = 1.16 +/- 0.47 cm(-1)/cm atm, and S-0-12(v) = 31.60 +/- 9.80 cm(-1)/cm atm. These vibrational band intensities combined with the theoretical spectral-line atlas make possible the generation of an ethylene spectrum at an arbitrary temperature. Such spectra prove useful to the planetary-atmosphere modeling-community. A web site is available where an individual can interact with the model and download a custom atlas. The URL is http://aurora.phys.utk.edu/(similar to)blass/ethyatl/. (C) 2001 Elsevier Science Ltd. All rights reserved