Variationally Computed IR Line List for the Methyl Radical CH₃

We present the first variational calculation of a hot-temperature ab initio line list for the CH 3 radical. It is based on a high-level ab initio potential energy surface and dipole moment surface of CH 3 in the ground electronic state. The ro-vibrational energy levels and Einstein A coefficients were calculated using the general-molecule variational approach implemented in the computer program TROVE. Vibrational energies and vibrational intensities are found to be in very good agreement with the available experimental data. The line list comprises 9 127 123 ro-vibrational states ( J ≤ 40) and 2 058 655 166 transitions, covering the wavenumber range up to 10 000 cm –1 and should be suitable for temperatures up to T = 1500 K.