  In this thesis work, two topics, triaxiality and reflection asymmetry, have
been discussed. Band structures in $^{163}$Tm were studied in a "thin" target
experiment as well as in a DSAM lifetime measurement. Two new excited bands
were shown to be characterized by a deformation larger than that of the yrast
sequence. These structures have been interpreted as Triaxial Strongly Deformed
bands associated with particle-hole excitations, rather than with wobbling.
Moreover, the Tilted-Axis Cranking calculations provide a natural explanation
for the presence of wobbling bands in the Lu isotopes and their absence in the
neighboring Tm, Hf and Ta nuclei. A series of so-called "unsafe" Coulomb
excitation experiments as well as one-neutron transfer measurements was carried
out to investigate the role of octupole correlations in the $^{238,240,242}$Pu
isotopes. Some striking differences exist between the level scheme and
deexcitation patterns seen in $^{240}$Pu, and to a lesser extent in $^{238}$Pu,
and those observed in $^{242}$Pu and in many other actinide nuclei such as
$^{232}$Th and $^{238}$U, for example. The differences can be linked to the
strength of octupole correlations, which are strongest in $^{240}$Pu. Further,
all the data find a natural explanation within the recently proposed
theoretical framework of octupole condensation.
