ABSTRACT
The 7000-8500 cm(-1) spectral region of (12)C(16)O(2) has been investigated using the high-resolution FT spectrometer of LPPM in Orsay. The two strongest bands in this region are the 10031 <-- 00001 and 10032 <-- 00001 bands centered at 8294 and 8192 cm(-1). Line intensities in these two bands and in the 40013 <-- 00001 and 40014 <-- 00001 bands have been measured. Using the method of effective operators, these line intensities have been included in a new fit of effective dipole-moment parameters to all available experimental data in the same spectral region of (12)C(16)O(2). The corresponding calculated line intensities of the 10031 <-- 00001 and 10032 <-- 00001 bands are compared with the experimental ones. Copyright 2000 Academic Press.
ABSTRACT
The effective operator approach is applied to the calculation of both line positions and line intensities of the (13)C(16)O(2) molecule. About 11 000 observed line positions of (13)C(16)O(2) selected from the literature have been used to derive 84 parameters of a reduced effective Hamiltonian globally describing all known vibrational-rotational energy levels in the ground electronic state. The standard deviation of the fit is 0.0015 cm(-1). The eigenfunctions of this effective Hamiltonian have then been used in fittings of parameters of an effective dipole-moment operator to more than 600 observed line intensities of the cold and hot bands covering the nu(2) and 3nu(2) regions. The standard deviations of the fits are 3.2 and 12.0% for these regions, respectively. The quality of the fittings and the extrapolation properties of the fitted parameters are discussed. A comparison of calculated line parameters with those provided by the HITRAN database is given. Finally, the first observations of the 2nu(1) + 5nu(3) and nu(1) + 2nu(2) + 5nu(3) absorption bands by means of photoacoustic spectroscopy (PAS) is presented. The deviations of predicted line positions from observed ones is found to be less than 0.1 cm(-1), and most of them lie within the experimental accuracy (0.007 cm(-1)) once the observed line positions are included in the global fit. Copyright 2000 Academic Press.
ABSTRACT
The (1 0(0) 5)1,2 --> (1 0(0) 4)1,2 and (1 0(0) 6)1,2 --> (1 0(0) 5)1,2 emission bands of 12C16O2 have been recorded near 4.5 µm by Fourier transform spectroscopy of a CO2 + N2 mixture excited by dc discharge. The spectroscopic parameters of the (1 0(0) v3)1,2 vibrational states with v3 = 0-6 have been obtained from a global rotational analysis of the six (1 0(0) v3)1,2 --> (1 0(0) (v3-1))1,2 emission bands (v3 = 1-6). The (1 0(0) 5)1,2 vibrational states of both 12C16O2 and 13C16O2 have been observed by direct absorption from the vibrational ground state by Intracavity Laser Absorption Spectroscopy near 12 700 and 12 400 cm-1, respectively. The rovibrational energy levels obtained by the two experimental techniques are discussed and compared with those calculated in the framework of the effective operator approach. Copyright 1999 Academic Press.
ABSTRACT
From spectra recorded at a resolution of 0.020 cm-1 of the flame CH4 + O2 at low pressure, six new vibrational transitions in Deltav3 = 1 with 2v1 + v2 = 5 had been recently identified [D. Bailly et al., J. Mol. Spectrosc. 182, 10-17 (1996)] based on the HITRAN 92 predictions. New calculations have shown good consistency with our assignments except for one transition, namely, (21(1)1)3e --> (21(1)0)3e for which discrepancies (reaching 0.2 cm-1) were found. It has been possible to resolve this issue using new emission spectra of CO2, vibrationally excited by active nitrogen and recorded with a Fourier transform spectrometer at a resolution of 6.3 x 10(-3) cm-1 in the 4-5 µm spectral region. Copyright 1998 Academic Press.
ABSTRACT
The effective operator approach has been applied to the calculation of line intensities of 12C16O2. Using the eigenfunctions of our reduced effective Hamiltonian (1992, J. Mol. Spectrosc. 156, 48-64) the experimental line intensities of cold and hot bands lying in the regions of 15, 10, and 5 µm have been fitted to parameters of the corresponding effective dipole moment matrix elements. The quality of fittings and the extrapolational properties of the fitted parameters are discussed. Formulas in terms of basic molecular properties for some of the parameters of the effective dipole moment matrix elements are derived. Values of these parameters calculated from the theoretical formulas using the force field and dipole moment expansions of Wattson and Rothman (1992, J. Quant. Spectrosc. Radiat. Transfer 48, 763-780) have been compared with corresponding fitted values. Copyright 1998 Academic Press. Copyright 1998Academic Press
