ExoMol line lists – XXIX. The rotation-vibration spectrum of methyl chloride up to 1200 K

Comprehensive rotation-vibration line lists are presented for the two main isotopologues of methyl chloride, ¹²CH3³⁵Cl and ¹²CH3³⁷Cl. The line lists, OYT-35 and OYT-37, are suitable for temperatures up to T = 1200 K and consider transitions with rotational excitation up to J = 85 in the wavenumber range 0–6400 cm⁻¹ (wavelengths λ > 1.56 μm). Over 166 billion transitions between 10.2 million energy levels have been calculated variationally for each line list using a new empirically refined potential energy surface, determined by refining to 739 experimentally derived energy levels up to J = 5, and an established ab initio dipole moment surface. The OYT line lists show excellent agreement with newly measured high-temperature infrared absorption cross-sections, reproducing both strong and weak intensity features across the spectrum. The line lists are available from the ExoMol database and the CDS database.