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

• Published in: Molecular physics 2008-09, Vol.106 (9-10), p.1233-1240
• Main Authors: Baldacci, A., Visinoni, R., Giorgianni, S., Nivellini, G.
• Format: Article
• Language: English
• Subjects: Fourier transform spectroscopy; monodeutero methyl chloride; vibration-rotation interactions
• ISSN: 0026-8976; 1362-3028
• DOI: 10.1080/00268970802116278

The infrared spectrum of CH 2 D 35 Cl 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 ν 9 (987 cm −1 ) and ν 3 (1435 cm −1 ) fundamentals. The unperturbed transitions of the weak ν 9 band have been analysed with the Hamiltonian of Watson to give accurate spectroscopic constants of the excited state. The transitions of the medium ν 3 band have been processed with a model which accounts for Coriolis and Fermi resonances with the ν 6 = 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 ν 3 region and through a deeper analysis performed in the ν 6 spectral range, where a number of weak features have been assigned to the 2ν 6 − ν 6 and ν 5 + ν 6 − ν 5 hot bands. Some spectroscopic parameters, in terms of an unperturbed level, have also been obtained for ν 5 = ν 6 = 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 ν 5 = 1 and ν 6 = 1 states.