IR astronomical data analysis needs highly accurate opacity data (line lists) for important molecules so called "weeds" in various interstellar environments. Sulfur Dioxide (SO2) is one of the 2nd class "weeds" for Herschel data analysis. Current widely used IR spectroscopic databases have very limited coverage for the main isotopologue 626, and far less or no coverage for minor isotopologues, so not suitable for highly accurate astronomical spectra analysis and simulations. Through the “Best Theory + High resolution Experimental Data” strategy, the consistency and reliability of quantum chemistry computations can be integrated with the best available accuracy of experimental IR data acquired in lab or astronomical observations. The whole merit of our SO2 isotopologue IR line lists is the prediction accuracy beyond the simple reproduction of existing data. Our Ames IR line lists are computed on a semi-empirically refined PES with a high quality ab initio dipole surface. After simple introduction of our strategy and the prediction accuracy of computed line lists: 0.01-0.02 cm-1 for line positions and 1-10% for intensity differences, we analyze the intensity data issues in current database. The isotopologue consistency of our IR intensities are good enough to carry out reliable high-resolution analysis for mixed-isotopologue spectra, and the rotational constants of minor isotopologues can be predicted within 0.01-0.02 MHz. We expect these SO2 line lists will facilitate incoming high-resolution IR astronomy spectra analysis.

Accurate IR line lists for SO2 isotopologues

254th National Meeting (2017)

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