Elucidation of the Ro-Vibrational Band Structures in the Silicon Tetrafluoride Spectra from Accurate Ab Initio Calculations.

We report the construction of comprehensive line lists for the three stable isotopologues of silicon tetrafluoride (28SiF4, 29SiF4, and 30SiF4) using a new effective Hamiltonian and dipole moment model built from accurate ab initio potential energy and dipole moment surfaces developed in this work. The vibrational energy levels were grouped into a series of polyads up to Pmax = 19, while the ro-vibrational energy levels were computed up to Jmax = 99. Each line list covers the spectral range 0-2500 cm-1 and contains almost 500 million transitions at T = 296 K, with each being generated from 685 vibrational states and sub-states. Most of the cold and hot band transitions computed in this work were not available in the literature beforehand. The absorption cross-sections computed from the produced line lists were successfully validated by direct comparison with the experimental data measured by Pacific Northwest National Laboratory at room temperature. Most of the ro-vibrational band structures observed in the experimental spectra can now be elucidated using the line lists proposed in this work.