Line intensities of 12C2H2 in the 7.7μm spectral region

Abstract

Absolute intensities of 414 lines are measured in eight bands of the 7.7 µm spectral region of the 12 C 2 H 2 molecule, with an average accuracy of 5%. Vibrational transition dipole moment squared values and empirical Herman-Wallis coefficients are obtained in order to model the rotational dependence of the transition dipole moment squared, except for some forbidden bands for which smoothed values are given. These data are used to calculate a line list for atmospheric or astrophysical applications.

Measurements of linestrengths, N2-, Ar-, He- and self-broadening coefficients of acetylene in the ν4+ν5 combination band using a cw quantum cascade laser

“…From measurements made with tunable diode lasers, Devi et al [10] derived N 2 -and air-broadening coefficients for a total of 29 lines between 1250 and 1380 cm -1 in the P and R branches. Individual line intensities of acetylene in the P and R branches of the ν 4 +ν 5 combination band have been measured at room temperature using Fourier Transform Infrared (FTIR) Spectroscopy in a number of studies [11][12][13][14]. Among recent measurements of spectroscopic parameters of acetylene in the ν 4 + ν 5 combination band, one should note the studies performed by Lepère's group [15][16][17][18][19][20].…”

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

“…Using the approach described above, we performed the leastsquares fittings of the line intensities measured in the 100, 7.7, 1.4, 1.3, 1.2 and 1 lm spectral regions [11][12][13][14][15]. The fittings were performed separately for each spectral region defined by the value of DP.…”

“…[25], confirming the values from the earlier measurements. Recently, two papers [13,15] to predict the line intensities of fourteen hot bands with MR not exceeding 10%, except for the ð2m 4 þ m 5 Þ 1 I À m 1 4 band, for which the mean residual is about 23%. For this weakest ''allowed'' band because of the partial cancellation of two principal contributions to the matrix element of the effective dipole moment operator (6) the parameter a 4 ðDV 4 ¼ 1; DV 5 ¼ 1Þ, which is absent in the fit of Ref.…”

“…[13,15,22,23] was performed. The weighting was carried out according to the declared experimental uncertainties of 5% in Refs.…”

“…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. In this paper, we present the new sets of the effective dipole moment parameters of acetylene for the modeling of the line intensities in the 100, 7.7, 1.4, 1.3, 1.2 and 1 lm spectral regions.…”