The CH3D absorption spectrum between 5000 and 6200 cm-1: Empirical line list and rovibrational assignments based on variational calculations

• An empirical list of more than 27600 lines is obtained for CH 3 D at room temperature between 5000 and 6200 cm -1 • This is the first quantitative line list for CH 3 D in the region • Rovibrational assignments rely on position and intensity agreement with a new variational line list and are validated by Lower State Combination Difference (LSCD) relations • About 10150 transitions are rovibrationally assigned to 43 bands, 24 of them being newly reported • More than 4000 upper state energies are determined with a typical uncertainty better than 2 × 10 -3 cm -1 The absorption spectrum of monodeuterated methane, CH 3 D, is studied in the 5000 – 6200 cm -1 region by high resolution Fourier transform spectroscopy at room temperature. An empirical list including 27600 lines was retrieved from two spectra, providing first intensity information in the region. Relying on the position and intensity agreements with a new variational line list, about 10150 transitions are rovibrationally assigned to 43 bands, 24 of them being newly reported. Variational positions deviate from measurements by up to 1.5 cm -1 and the variational band intensities are found in agreement with measurements within typically 10%. All the reported assignments are confirmed by Lower State Combination Difference (LSCD) relations i.e. all the upper state energies (4039 in total) have coinciding determinations through several transitions (up to 8). The energy values are determined with a typical uncertainty better than 2 × 10 -3 cm -1 . The intensity sum of the transitions assigned in the region represents 80.4 % of the total experimental intensities in the region.