Temperature dependence of the absorption spectrum of CH4 by high resolution spectroscopy at 81 K: (II) The icosad region (1.49-1.30 mu m)

0346595 - ÚFCH JH 2011 RIV GB eng J - Journal Article
Campargue, A. - Wang, L. - Kassi, S. - Mašát, Milan - Votava, Ondřej
Temperature dependence of the absorption spectrum of CH4 by high resolution spectroscopy at 81 K: (II) The icosad region (1.49-1.30 mu m).
Journal of Quantitative Spectroscopy and Radiative Transfer. Roč. 111, č. 9 (2010), s. 1141-1151. ISSN 0022-4073. E-ISSN 1879-1352
R&D Projects: GA ČR GA202/09/0800
Institutional research plan: CEZ:AV0Z40400503
Keywords : methane * CH4 * absorption spectroscopy
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 2.331, year: 2010

The high resolution absorption spectrum of methane has been recorded at liquid nitrogen temperature by differential absorption spectroscopy between 6717 and 7351 cm(-1) (1.49-1.36 mu m) using a cryogenic cell and a series of distributed feed back (DFB) diode lasers. The investigated spectral region corresponds to the very congested low energy part of the icosad for which the HITRAN database provides neither rovibrational assignments nor the lower state energies. The positions and strengths at 81 K of 9389 transitions were obtained from the spectrum analysis. The minimum value of the measured line intensities (at 81 K) is on the order of 10(-26) cm/molecule. From the variation of the line strength between 81 K and 296 K, the low energy values of a total of 4646 transitions were determined. They represent 79.4% and 68.4% of the total absorbance in the region at 81 and 296 K. respectively, and include 28 transitions assigned to the nu(2)+4 nu(4) band near 6765 cm(-1).
Permanent Link: http://hdl.handle.net/11104/0187584