EN
Stability of motions for different potential functions describing vibrational motions of rotating molecule has been discussed. It was shown that an equilibrium position for nonrotating r_{0} and rotating r_{J} molecules for almost all the examined potentials is a node, but for the molecule described by the soft body model a critical value of rotation quantum number J_{c} occurs above which r_{0} is a saddle point, and the stable motion may occur only around r_{J}.