Accurate potential energy surface, dipole moment surface, and IR line lists for OCS isotopologues up to 2000 K

• OCS PES refinement with σ rms <0.01 cm -1 and DMS fitting σ rms <1.5×10 -7 au in 0 – 15000 cm -1 • Combine Ames, EH and experimental data to determine more consistent empirical line positions • Ames-296K line list has 9 million transitions from 12 isotopologues in 0 – 15,000 cm -1 • Ames-2000K line list has 7 billion transitions from 7 isotopologues, covering T up to 2000 K • Better agreements with PNNL spectra, compared to HITRAN and ExoMol We report high-quality IR line lists of carbonyl sulfide (OCS) computed using an ab initio potential energy surface (PES) refined with selected energy levels from HITRAN2020 and experimental energies for highly excited vibrational states, and CCSD(T)/aug-cc-pV(T/Q/5+d)Z dipole moment surfaces (DMS). With PES accuracy σ rms < 0.01 cm -1 for 16 O 12 C 32 S levels and DMS fitting σ rms = 1.3×10 -7 au for potential energy < 15,000 cm -1 , room-temperature IR line lists are generated for 12 OCS isotopologues in the 0–15,000 cm -1 range with S 296K > 10 -31 cm -1 /molecule.cm -2 , then combined into a composite line list of 9 million transitions, denoted Ames-296K. For high-temperature applications, an Ames-2000K OCS line list is constructed in the same range, including 7 OCS isotopologues, with J ≤ 240 and E ' ≤ 23,000 cm -1 for 16 O 12 C 32/34 S. The Ames line lists are compared to HITRAN, CDMS, JPL(2010) near-IR line list, ExoMol line list for 16 O 12 C 32 S, and high-resolution experimental IR studies. Data issues and discrepancies are identified and discussed. The accuracy of energy levels and line positions in the Ames line lists have been further enhanced using reliable experimental-based effective Hamiltonian (EH) models from HITRAN, or more consistent 0 th -2 nd order adjustments derived from the band-by-band comparisons between E Ames and E MARVEL , E CDMS , and experimental data and models. We demonstrate the reliability and consistency of theoretical calculations may be utilized to determine more consistent empirical line positions, compared to direct MARVELization. The Ames-296K line list is evaluated against Pacific Northwest National Laboratory experimental cross sections, showing widespread improvements over HITRAN and ExoMol line lists in the range of 600-6500 cm -1 . The Ames line lists with empirically corrected line positions will provide accurate, reliable, and more complete IR predictions to facilitate OCS spectra analysis and modeling in atmospheric and exoplanetary studies. The PES, DMS, and line list files are available online at 10.5281/zenodo.13906150 and 10.48667/6hcw-n617.