  Fragment-fragment-$\gamma$ triple coincidence measurements of the
$^{28}$Si~$+$~$^{28}$Si reaction at E$_{\rm c.m.}$~=~55.8 MeV, carefully chosen
to populate a well known quasi-molecular resonance in $^{56}$Ni, have been
performed at the VIVITRON tandem facility by using the Eurogam Phase~II
$\gamma$-ray spectrometer. In the $^{28}$Si~$+$~$^{28}$Si reaction, the
resonant behavior of the $^{28}$Si $+$ $^{28}$Si exit-channel is clearly
observed by the present fragment-fragment coincidence data. The more unexpected
result is the spin disalignment of the $^{28}$Si $+$ $^{28}$Si resonance. This
has been demonstrated first by the measured angular distributions of the
elastic 0$^{+}$, inelastic 2$^{+}$ and mutual excitation channels
2$^{+}-2^{+}$, which are dominated by a unique and pure partial wave with L =
38 ${\rm \hbar}$, and has been confirmed by measuring their particle-$\gamma$
angular correlations with Eurogam Phase II. The spin disalignment supports new
molecular model predictions, in which the observed resonance would correspond
to the ''Butterfly mode''. A discussion concerning the {\it spin alignment and
spin disalignment} for different systems : $^{12}$C~$+$~$^{12}$C,
$^{24}$Mg~$+$~$^{24}$Mg and $^{28}$Si~$+$~$^{28}$Si will be given.}
