High-resolution FTIR spectroscopy of CH₂D³⁵Cl: rovibrational analysis of the ν₃, ν₉ fundamentals and the 2ν₆ - ν₆, ν₅ + ν₆ - ν₅ hot bands

Agostino Baldacci (1) , Raffaella Visinoni (1) , Santi Giorgianni (1) , Giandomenico Nivellini (2)

1 Dipartimento di Chimica Fisica
2 Dipartimento di Chimica Fisica e Inorganica [Bologna]

The infrared spectrum of CH₂D³⁵Cl has been measured on a Bomem Model DA3.002 Fourier transform spectrometer with a resolution of about 0.004 cm^-1 and interpreted in the regions of the ν₉ (987 cm^-1) and ν₃ (1435 cm^-1) fundamentals. The unperturbed transitions of the weak ν₉ band have been analysed with the Hamiltonian of Watson to give accurate spectroscopic constants of the excited state. The transitions of the medium ν₃ band have been processed with a model which accounts for Coriolis and Fermi resonances with the v₆ = 2 state, located 16 cm^-1 below the fundamental level. The rovibrational energy levels of this state, otherwise dark, have been obtained from the perturbation-allowed transitions observed in the ν₃ region and through a deeper analysis performed in the ν₆ spectral range, where a number of weak features have been assigned to the 2ν₆ - ν₆ and ν₅ + ν₆ - ν₅ hot bands. Some spectroscopic parameters, in terms of an unperturbed level, have also been obtained for v₅ = v₆ = 1. Ground state constants have been improved using ground state combination differences (GSCDs) assembled from a-, b- and c-type transitions of four fundamentals. These new values allowed in turn the revision of the spectroscopic parameters of the coupled v₅ = 1 and v₆ = 1 states.

Mots clés: Physical Sciences

Agostino Baldacci, Raffaella Visinoni, Santi Giorgianni, Giandomenico Nivellini. High-resolution FTIR spectroscopy of CH₂D³⁵Cl: rovibrational analysis of the ν₃, ν₉ fundamentals and the 2ν₆ - ν₆, ν₅ + ν₆ - ν₅ hot bands. Molecular Physics, 2008, 106 (09-10), pp.1233-1240. ⟨10.1080/00268970802116278⟩. ⟨hal-00513205⟩