QUALITATIVE ANALYSIS OF MOLECULAR ROTATION STARTING FROM INTER-NUCLEAR POTENTIAL Ch. Van Hecke, D. A. Sadovskií, and B. I. Zhilinskií Université du Littoral, B.P. 5526, 59379 Dunkerque Cedex, France Draft: Dunkerque, February 15, 1999 We study how qualitative features of the molecular rotational dynamics can be derived directly from the internuclear (vibrational) potential. This approach is presented on the example of a tetrahedral molecule A_4 using several increasingly elaborated models of the potential. PACS: 33.15.Mt Rotation, vibration, and vibration-rotation constants 33.20.Vq Vibration-rotation analysis European Phys. J. D 7, 199-209 (1999).