Highly accurate potential energy surface and dipole moment surface for nitrous oxide and 296K infrared line lists for 14N216O and minor isotopologues

Abstract

To facilitate the data analysis of current and future high-resolution space telescope missions, we adopt ‘Best Theory + Reliable High-resolution Experiment’ (BTRHE) strategy to develop highly accurate infrared line lists for nitrous oxide (N2O). The ‘Ames-1’ potential energy surface (PES) is a CCSD(T)/aug-cc-pVQZ PES refined using selected HITRAN experimental data, with σ rms = 0.02–0.03 cm-1 for five isotopologues. The ‘Ames-1’ dipole moment surface (DMS) is fitted from CCSD(T)/aug-cc-pV(T,Q,5)Z dipoles extrapolated to one electron basis set limit. Using the Ames-1 PES and DMS, Ames-296K line lists are computed in the full range of 0–15,000 cm-1 for 12 N2O isotopologues, with S 296K ≥ 10−31 cm-1/molecule.cm-2. The reliability and consistency of Ames-296K intensity predictions (S Ames) are demonstrated through comparisons with HITRAN (S HITRAN), NOSL-296 (S NOSL), recent observed intensities (S obs) and Effective Dipole Model (EDM) intensities (S EDM). Agreements and discrepancies are discussed, along with preliminary uncertainty estimate for S Ames. The S Ames provides a good constraint to prevent substantial errors in intensity predictions (e.g. for weak bands and minor isotopologues) and can be further improved. Ames-296K and NOSL-296 may complement each other to provide improved input for future database updates, combining the strengths of EH/EDM and BTRHE approaches. Data available at https://doi.org/10.5281/zenodo.7888194 and https://doi.org/10.48667/9kmk-0334.