title: Photoabsorption Assignments for the C̃1B2← X̃1A1Vibronic Transitions of SO2, Using New Ab Initio Potential Energy and Transition Dipole Surfaces.
abstract: The high resolution spectroscopy of the SO2molecule is of great topical interest, in a wide variety of contexts ranging from origins of higher life, to astrophysics of the interstellar medium, to environmental chemistry. In particular, the C̃1B2← X̃1A1UV photoabsorption spectrum has received considerable attention. This spectrum exhibits a highly regular progression of ∼20 or so strong peaks, spaced roughly 350 cm-1apart, which is comparable to the C̃1B2bending vibrational frequency. Accordingly, they have for decades been largely attributed to the (1, v2', 2) ← (0, 0, 0) bend progression. Using a highly accurate new ab initio potential energy surface (PES) for the C̃1B2state, we compute vibrational energy levels and wave functions, and compare with a photoabsorption calculation obtained using the same PES and corresponding C̃1B2← X̃1A1transition dipole surface (TDS). We find that the above putative assignment is incorrect, contradicting even general qualitative trends-thus necessitating a very different dynamical picture for this highly unusual molecule.
authors.affiliation: Department of Chemistry and Biochemistry, Texas Tech University , Lubbock, Texas 79409-1061, United States.
authors.forename: Praveen
authors.identifier: http://orcid.org/0000-0001-7727-6652
authors.initials: P
authors.lastname: Kumar
authors.affiliation: Department of Chemistry and Chemical Biology, University of New Mexico , Albuquerque, New Mexico 87131, United States.
authors.forename: Bin
authors.identifier: http://orcid.org/0000-0003-2696-5436
authors.initials: B
authors.lastname: Jiang
authors.affiliation: Department of Chemistry and Chemical Biology, University of New Mexico , Albuquerque, New Mexico 87131, United States.
authors.forename: Hua
authors.identifier: http://orcid.org/0000-0001-9901-053X
authors.initials: H
authors.lastname: Guo
authors.affiliation: Department of Chemistry and Biochemistry, University of Maryland , College Park, Maryland 20742, United States.
authors.forename: Jacek
authors.initials: J
authors.lastname: Kłos
authors.affiliation: Department of Chemistry and Biochemistry and Institute for Physical Science and Technology, University of Maryland , College Park, Maryland 20742, United States.
authors.forename: Millard H
authors.initials: MH
authors.lastname: Alexander
authors.affiliation: Department of Chemistry and Biochemistry, Texas Tech University , Lubbock, Texas 79409-1061, United States.
authors.forename: Bill
authors.initials: B
authors.lastname: Poirier