  Based on a recent experimental finding which may suggest the existence of a
tri-nuclear molecular structure before the cold ternary fragmentation of
$^{252}$Cf takes place, we solved the eigenvalue problem of a certain class of
vibrations which are very likely to occur in these molecules. These
oscillations are the result of the joined action of rotations of the heavier
fragments and the transversal vibrations of the lighter spherical cluster with
respect to the fission axis. In the calculation of the interaction between the
heavier fragments we took into account higher multipole deformations, including
the hexadecupole one, and introduced a repulsive nuclear part to insure the
creation of a potential pocket in which a few molecular states can be
accommodated. The possibility to observe the de-excitation of such states is
discussed in connection with the molecular life-time.
