On the high resolution spectroscopy and intramolecular potential function of SO2

Two weak stretching bands, ν1 + 3ν3 and 3ν1 + ν3, of the sulfur dioxide molecule have been recorded at high resolution and analyzed for the first time with using a Fourier transform Bruker IFS-120 HR interferometer. About 1000 transitions with Jmax. = 51, Kamax.=16, and 900 transitions with Jmax. = 53, Kamax.=16 have been assigned to the bands ν1 + 3ν3 and 3ν1 + ν3, respectively. Analysis of the recorded spectra was made using the model of isolated vibrational states. Parameters obtained from the fit reproduce the initial experimental ro-vibrational energies with the rms deviation of 0.0006 and 0.0012 cm−1 for the bands, 3ν1 + ν3 and ν1 + 3ν3, respectively. The problem of determination of the intramolecular potential function of SO2 is discussed.