Accurate ro-vibrational spectra of triatomic molecules with Giant Renner-Teller of linear-bent coupling
Résumé
A general approach and its implementation for calculating the rovibronic levels and spectra of rigid or floppy Renner-Teller triatomic molecules, which is not limited in the number and quantum numbers (Λ, S) of electronic states, is presented [1]. Exact kinetic energy operator is used. Model and full spin-dependent interactions (spin-orbit or spin-spin) can be treated. The case of strong Renner-Teller coupling (ε≥1) is specially studied and it is shown that the proposed implementation provides very accurate and stable results for this complicated problem. The program allows for both contracted and full 3D solution of vibration program. The latter is especially important for multiple-minima potentials. Few examples illustrate the performance of the code: BF2[1] with strong Renner-Teller coupling; HBF[1] as a coupled linear-bent system; CCN[2] radical as a case study of accurate vibronic transition intensities calculation for Renner-Teller system, SiNC/SiNC[3] as multiple-minima system, and finally cyanides of Cu, Ag and Au as an example of heavy elements[4].