A full-dimensional ab initio potential energy surface and rovibrational spectra for the Ar-SO2 complex

We present a full-dimensional potential energy surface for Ar-SO2 which involves three intramolecular Q(1), Q(2) and Q(3) normal modes for the v(1) symmetric stretching, v(2) bending and v(3) asymmetric stretching vibrations of SO2. The intermolecular potential was computed at the [CCSD(T)]-F12a level with aug-cc-pVTZ basis set plus the midpoint bond functions (3s3p2d1f1g). Three vibrationally averaged potentials of Ar-SO2 with SO2 in the ground state as well as the v(1) and v(3) excited states were generated by integrating three intramolecular coordinates. Each potential has a global minimum with the non-planar geometry and two saddle points. The radial discrete variable representation (DVR)/angular finite basis representation (FBR) method and Lanczos algorithm were utilized to calculate the rovibrational bound states and energy levels of Ar-SO2. The vibrational band origin shifts for this complex in the v(1) and v(3) regions of SO2 were determined to be - 0.0970 and - 0.7537 cm(-1), respectively. The calculated origin shifts as well as the microwave and infrared transition frequencies agree well with available experimental results.