Coupling. Rovibrational Interactions. Fermi Resonances

8 Coriolis Coupling. Rovibrational Interactions. Fermi Resonances 

Coriolis coupling constants are usually calculated from the fundamental vibrations by the methods of Meal and Polo [1, 2] and Smith and Mills [3]. Only the Coriolis coupling constants = 0.07755(16) for HN3 [4] and 0.093(8) for DN3 [5] were obtained from rovibrational spectra. The calculated values are as follows [1]  

Perturbations of the vibrational fundamentals of HN3 and DN3 are extensive. The experimental observations are described separately for each isotopomer. 

Perturbations were observed in the upper levels K = 0 to 2 of v The interactions take place by enharmonic resonance for K = 0 and K = 1. The vibrational levels Vg or Vg or both are probably involved in the first case, whereas in the second one, V2 + 2vg is possibly interacting. The small anomaly at the K = 2 level of v, is due to two different perturbations [6]. 

The main resonance in Vg is a strong first-order a-Coriolis perturbation by Vg which strongly effects the positions of the K levels in both bands [10]. Fundamentals from a low- 

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