Configurational-vibrational degeneracy in the vibration-rotation spectrum of a nonrigid molecule

A combined description of the configurational and vibrational degeneracy in the vibration-rotation spectrum of a nonrigid molecule is suggested on the basis of a concept of the coordinate spin. A detailed analysis of the algebraic properties of this spin is carried out. As a concrete application, the effective operators of the physical quantities of the NH{sub 3} molecule in its ground electronic state are qualitatively represented as a Taylor series in the dynamic variables, taking into account the above-mentioned degeneracies. 8 refs., 2 tabs.