C3H4N2 1-Propyne - dinitrogen

The rovibrational speetrum near 3334 em shows (A,E) state splittings eaused by methyl-group internal rotation. The A state microwave transitions are split because of nitrogen (N2) internal rotation which, however, could not be resolved in the infrared region (E state microwave transitions were not searched for [97Tse]). In what follows A and B pairs of state refer to nitrogen, A and E to methyl internal motion. 

Quantum State Molecular Constants Reference Method 

Barrier height for the hindered N2 motion 71 em Analysis of infrared speetra 

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