13C16O2:: Global treatment of vibrational-rotational spectra and first observation of the 2ν1+5ν3 and ν1+2ν2+5ν3 absorption bands

The effective operator approach is applied to the calculation of both line positions and line intensities of the (CO2)-C-13-O-16 molecule. About 11 000 observed line positions of (CO2)-C-13-O-16 selected from the literature have been used Co 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 v(2) and 3v(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 hue parameters with those provided by the HITRAN database is given. finally, the first observations of the 2v(1) + 5v(3) and v(1) + 2v(2) + 5v(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. (C) 2000 Academic Press.