Rotational and Rovibrational Spectroscopy of the v8=1 and 2 Vibrational States of CH3NC

Petr Pracna (1) , Jiří Urban (2) , Ondřej Votava (2) , Štěpán Urban (3) , Zuzana Meltzerová (3) , Veli-Matti Horneman (4)

1 J. Heyrovský Institute of Physical Chemistry
2 J. Heyrovsky Institute of Physical Chemistry
3 Department of Analytical Chemistry
4 Department of Physics

The lowest frequency vibration-rotation band ν8, corresponding to the degenerate CNC bending vibration of methyl isocyanide (CH3NC) with band center at 267.3 cm-1, was studied by FTIR spectroscopy between 215 and 320 cm-1 and rotational spectroscopy in the range from 201 to 383 GHz in order to describe the vibration-rotation dynamics with inclusion of all important anharmonic and vibration-rotation interactions. Assignments extended to higher-K rotational states in both vibration-rotation and rotational spectra reveal a resonance crossing with the v8 = 2 overtone level due to a local anharmonic Fermi resonance. The simultaneous analysis of both types of data provides a fully quantitative reproduction of the experimental data as well as a preliminary characterization of the v8 = 2 level. The parallel component of the overtone band nu8 with band center at 524.6 cm-1 was assigned for the first time from spectra in the region from 480 to 585 cm-1 together with the hot bands 2nu8-nu8 in the region of the fundamental band.

Mots clés: Physical Sciences

Domaines: Matière Condensée [cond-mat]

Petr Pracna, Jiří Urban, Ondřej Votava, Štěpán Urban, Zuzana Meltzerová, et al.. Rotational and Rovibrational Spectroscopy of the v8=1 and 2 Vibrational States of CH3NC. Molecular Physics, 2011, pp.1. ⟨10.1080/00268976.2011.605775⟩. ⟨hal-00722801⟩