Line list of 12CH4 in the 4300-4600 cm-1 region

Four spectra of normal samples of CH4 in the 4300-4600 cm-1 region were recorded by using a Fourier transform spectrometer in Reims, France at long paths (202 m, 602 m, 1604 m, and 1804 m) and different pressures. Additional spectra of 12CH4 covering the same region were obtained at 80-123 K, and 93 m path length at SOLEIL Synchrotron in Paris for different pressures and were used to measure low-J lines. Line positions and intensities were retrieved by non-linear least-squares curve-fitting procedures and analyzed using effective Hamiltonian and effective dipole transition moment models. A new measured line list contains positions and intensities for 14151 absorption features. Quantum assignments were made for more than 10304 transitions of 12CH4, which represent ~99% of the integrated line intensity observed in this region. Some 1699 hot band transitions for (Dyad – Tetradecad) system were assigned. The resulting list of lines is significantly more accurate than previous empirical compilations. Positions of 8605 cold band transitions for (GS – Octad) system were fitted with an RMS standard deviation of 0.0014 cm-1. The sum of observed intensities between 4300 and 4600 cm-1 fell within 8% of the predicted value from ab initio variational calculations reported in the TheoReTS database (http://theorets.univ-reims.fr ; http://theorets.tsu.ru).