6533b82afe1ef96bd128cb2c

RESEARCH PRODUCT

High resolution analysis of the SO2 spectrum in the 2600–2900cm−1 region: 2ν3, ν2+2ν3−ν2 and 2ν1+ν2 bands

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Abstract Infrared spectrum of the SO 2 molecule was recorded with high resolution in the 2600– 2900 cm − 1 region. Spectrum was recorded with the Fourier transform interferometer Bruker IFS-120 HR in Oulu (Finland) with the pressure of 111 Pa and the absorption path length of 163.2 m that allowed us to record 2 ν 3 and 2 ν 1 + ν 2 weak bands. The 2 ν 3 band discussed earlier by Lafferty et al., was re-analyzed, and considerably more information was extracted from the spectrum (more than 3800 transitions of the 2 ν 3 band were assigned in the experimental spectrum with maximum values of quantum numbers, J max . = 76 and K a max . = 26 ). On the basis of the procedure discussed in Ulenikov et al., about 760 transitions of the ν 2 + 2 ν 3 − ν 2 hot band ( J max . = 49 and K a max . = 13 ), were assigned, and the rotational structure of the (012) vibrational state was determined for the first time with high accuracy. Very weak band, 2 ν 1 + ν 2 , was analyzed also for the first time, and about 1250 transitions with J max . = 43 and K a max . = 17 were assigned in the spectrum. Information, obtained from the experimental data, was used in the fit for the determination of spectroscopic parameters of the states (002), (012), and (210). In this case, some earlier undiscussed sets of interacting ro-vibrational states were found, and resonance interactions between the states (002)/(130) and (012)/(140) were taken into account. Obtained from the fit, 36 parameters reproduce more than 5800 initial transitions of all three bands with the accuracy close to experimental uncertainties (rms deviation is 0.00021 cm − 1 , 0.00031 cm − 1 and 0.00014 cm − 1 for the 2 ν 3 , ν 2 + 2 ν 3 − ν 2 and 2 ν 1 + ν 2 bands, respectively).