Special issue: 22nd colloquium on high-resolution molecular spectroscopy HRMS Dijon 2011 (Part 2) high resolution infrared synchrotron study of CH_2D~(81)Br: Ground state constants and analysis of the v_5, v_6 and v_9 fundamentals

摘要

The high resolution infrared absorption spectrum of CH)2D~(81)Br has been recorded by Fourier transform spectroscopy in the range 550-1075 cm~(-1), with an unapodized resolution of 0.0025 cm~(-1), employing a synchrotron radiation source. This spectral region is characterized by the v 6 (593.872 cm~(-1)), v_5 (768.710 cm~(-1)) and v_9 (930.295 cm~(-1)) fundamental bands. The ground state constants up to sextic centrifugal distortion terms have been obtained for the first time by ground-state combination differences from the three bands and subsequently employed for the evaluation of the excited state parameters. Watson's A-reduced Hamiltonian in the Ir representation has been used in the calculations. The v_6=1 level is essentially free from perturbation whereas the v_5=1 and v_9=1 states are mutually interacting through a-type Coriolis coupling. Accurate spectroscopic parameters of the three excited vibrational states and a high-order coupling constant which takes into account the interaction between v_5 and v_9 have been determined.