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The proton-rich nuclei in the A ? 60 mass region provide an excellent laboratory for studying the interplay between single-particle and collective nuclear excitations. In order to increase the sensitivity of spectroscopic studies of these nuclei, a new method of channel selection based on the measurement of the total energy of all ? rays and charged particles emitted in fusion-evaporation reactions has been developed. This method has been used to identify and study deformed and superdeformed (SD) rotational bands in 62 Zn and the N = Z nucleus 60 Zn. Two sets of strongly coupled rotational bands have been identified in 62 Zn and have been observed up to the terminating states of their respective configurations. Lifetime measurements indicate that the transition quadrupole moments in these bands decrease as termination is approached. These results represent the first observation of the terminating states of rotational bands in the A ? 60 mass region and confirm the predicted loss of collectivity associated with the phenomenon of smooth band termination. The first superdeformed rotational band in the A ? 60 mass region has also been identified in 62 Zn, establishing a new region of superdeformation for nuclei with neutron and proton numbers N , Z [approximate] 30. The doubly-magic superdeformed band in the N = Z nucleus 60 Zn has been identified. This band corresponds to filling the single-particle orbitals up to the large SD shell gaps at N , Z = 30 and is the natural reference core for the study of A ? 60 superdeformation. In addition, the observation of linking transitions connecting this band to normal deformed (ND) states provides the first spin, parity, and excitation energy measurements for A ? 60 SD states. The stretched- E 2 character and relatively large B (E 2) values of these linking transitions indicate that the decay-out mechanism in 60 Zn differs significantly from that observed in heavier nuclei. Doctor of Philosophy (PhD)

As part of a systematic survey of superdeformation in nuclei in the vicinity of ¹⁴³Eu, six superdeformed bands in ¹⁴²Sm, ¹⁴²Eu and ¹⁴⁴Eu have been studied by their Υ-ray decay following heavy-ion fusion-evaporation reactions. All of these bands are based on a "second minimum" shell gap associated with the superdeformed (2:1 prolate ellipsoid of rotation) nuclear shape at neutron number N=80 and proton number Z=63. The first band in ¹⁴²Sm and the band in ¹⁴²Eu have been studied with the 8π spectrometer, while the bands in ¹⁴⁴Eu and the excited band in ¹⁴²Sm have been discovered with the GAMMASPHERE array. The Υ-ray decays of these superdeformed structures are compared to collective rotational models, and specifically to state-of-the-art Cranked Shell Model (CSM) calculations for Nilsson, Woods-Saxon, and Hartree-Fock models of the nuclear potential. The predicted roles of specific orbitals in the A~140 mass region are compared to quantities derived from the experiments and where possible, configurations with respect to an ¹⁴³Eu core are proposed. The first ¹⁴²Sm band consists of 19 Υ-ray transitions with an intensity of 0.5% of the reaction channel, and its behaviour is best described in the calculations as an ¹⁴³Eu superdeformed core with a hole in an Nosc=5 proton orbital. The second excited band consists of 15 transitions with an intensity ~ 20% that of the first band, of which the transitions above ~ 1 MeV are identical in energy to those in a ¹⁴⁶Gd band. This new band, which represents the second example of a two-proton, two-neutron identical bands pair, is most likely a ¹⁴⁶Gd superdeformed core with four holes in low Nosc orbitals. Structures based on simple excitations of the proton hole of the first band likely comprise a quasi-continuum ridge structure. The ¹⁴²Eu band has 15 transitions and an intensity of 1.2%. The detailed behavior of this band suggests that its configuration is an Nosc=5 neutron hole in the ¹⁴³Eu core. Such a configuration is not predicted to be energetically favourable. The three ¹⁴⁴Eu bands all have population intensities of < 0.2 % relative to the reaction cross-section. Two of the ¹⁴⁴Eu bands, with 17 and 18 transitions respectively, are quite likely Nosc=6 neutron particle states coupled to the ¹⁴³Eu core. The behavior of the third band indicates occupation of an Nosc=7 neutron intruder which does not influence the shape of the ¹⁴³Eu core. Doctor of Philosophy (PhD)