Let us emphasize at this point that the tetrahedral configurations, as predicted
by theory, are markedly non-axial and, therefore, are expected to strongly mix
components of wave-functions with various quantum numbers : the strongest
component associated with the geometry of shapes based on the
spherical harmonics should be
. Theoretical calculations based on the
generalised collective rotor Hamiltonian that includes terms of the third order
in angular momentum2 indicate that the structure of
the wave-function of the
state is exceptional since, in contrast to states
with
, it must not manifest the tetrahedral symmetry. In other
words, for
the tetrahedral symmetry is excluded; actually
state
wave-function manifest an axial symmetry. Consequently, the role of the
state, often treated as a member of the (expected to be) the tetrahedral band,
is special in that even if connected to the
state via an E2 transition,
in principle possible due to an expected to be strong a K-mixing, its underlying
symmetry must not be tetrahedral. Our experiement, similarly to the preceding
ones, gives no sign of the
transition either what signifies that the
corresponding E2 transition, if exists, must be very weak.