Global fitting of line intensities of acetylene molecule in the infrared using the effective operator approach

Effective dipole moment parameters of 12C2H2 for the 100, 7.7, 1.4, 1.3, 1.2 and 1.0 μm regions

“…For the reader's convenience, we briefly summarize here the approach used for the line intensity calculations published in our previous reports [2,3]. As a general form, the intensity S V 0 J 0 e 0 VJe expressed as cm À1 /(molecule cm À2 ) at a temperature T (K) of an absorption line corresponding to the transition V 0 J 0 e 0 VJe, where V and J are the vibrational index and the angular momentum quantum number, respectively, and e = ±1 is the parity, is related to the…”

“…(5), the vibrational-rotational transition moment squared can be written in the following way [2,3]:…”

“…The functions U DJDK ðJ; KÞ for DK ¼ AE2 and vibrational functions [3]. The Herman-Wallis type functions DV F D' 4 D' 5 DJDK ðJ; KÞ are also given in Ref.…”

“…Some astrophysical and industrial applications require data on the spectral line parameters at higher temperatures, and these parameters could be obtained using theoretical modeling. This paper continues the series of our studies dealing with the theoretical modeling of the acetylene line intensities within the framework of the effective operator approach [2][3][4][5][6][7][8][9]. This approach is based on the effective Hamiltonian [10] that globally describes the line positions of all of the vibrational-rotational transitions of the C 2 H 2 molecule in its ground electronic state.…”

“…The parameters of the effective dipole moment operator are fit to the observed line intensities. The effective dipole moment parameters of acetylene that may be used for the line intensity calculations in a wide spectral range from 13.6 to 1.5 lm have been published previously [3][4][5][6][7][8][9]. Recent measurements of the acetylene line intensities [11][12][13][14][15] allow for the recovery of the sets of effective dipole moment parameters, which extend this spectral range and considerably improve line intensity modeling in the 7.7 lm region.…”