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Title: Survey of the high resolution infrared spectrum of methane ({sup 12}CH{sub 4} and {sup 13}CH{sub 4}): Partial vibrational assignment extended towards 12 000 cm{sup −1}

We have recorded the complete infrared spectrum of methane {sup 12}CH{sub 4} and its second most abundant isotopomer {sup 13}CH{sub 4} extending from the fundamental range starting at 1000 cm{sup −1} up to the overtone region near 12 000 cm{sup −1} in the near infrared at the limit towards the visible range, at temperatures of about 80 K and also at 298 K with Doppler limited resolution in the gas phase by means of interferometric Fourier transform spectroscopy using the Bruker IFS 125 HR prototype (ZP 2001) of the ETH Zürich laboratory. This provides the so far most complete data set on methane spectra in this range at high resolution. In the present work we report in particular those results, where the partial rovibrational analysis allows for the direct assignment of pure (J = 0) vibrational levels including high excitation. These results substantially extend the accurate knowledge of vibrational band centers to higher energies and provide a benchmark for both the comparison with theoretical results on the one hand and atmospheric spectroscopy on the other hand. We also present a simple effective Hamiltonian analysis, which is discussed in terms of vibrational level assignments and {sup 13}C isotope effects.
Authors:
;  [1] ;  [2] ;  [1] ;  [3] ;  [1] ;  [4] ; ;  [1]
  1. Physical Chemistry, ETH Zürich, CH-8093 Zürich (Switzerland)
  2. (Russian Federation)
  3. (Switzerland)
  4. (Germany)
Publication Date:
OSTI Identifier:
22413333
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 23; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; EXCITATION; FOURIER TRANSFORMATION; HAMILTONIANS; INFRARED SPECTRA; ISOTOPE EFFECTS; METHANE; SPECTROSCOPY; VIBRATIONAL STATES