Investigation of the Ground Vibrational State of CD 3OH by a New "Ritz" Program for Direct Energy Level Fitting

Abstract

The complete absorption spectrum of CD 3OH between 30 and 1200 cm −1 has been measured on the Bruker Fourier transform spectrometer of the Physical Chemistry Institute of the University of Giessen. In the present work we present the assignment of more than 20 000 lines between 30 and 850 cm −1, corresponding to transitions within the vibrational ground state of the molecule. These assignments have been performed with the help of a new computer program which evaluates the energies of the involved levels by the Rydberg-Ritz combination principle and can tackle such perturbations as Fermi-type resonances or Coriolis interactions. Up to now this program has evaluated the energies of 1789 levels belonging to A-type symmetry and of 2417 levels belonging to E-type symmetry, all in the vibrational ground state of the molecule. The evaluation of the energy level values allows comparisons between different isotopic species.