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Measuring the fusion excitation function for an isotopic chain of projectile nuclei provides a stringent test of a microscopic description of fusion. We report the first measurement of the fusion excitation function at near-barrier energies for the 19 O + 12 C system. The measured excitation function is compared with the fusion excitation function of 18 O + 12 C. A significant enhancement in the fusion probability of 19 O ions with a 12 C target as compared to 18 O ions is observed. The experimental cross-sections observed at near-barrier energies are compared with a state-of-the-art microscopic model.

A study of high spin states in the odd-neutron isotones 239 Pu and 237 U is reported. Striking differences were found in the high-spin properties of rotational bands built on the 1 /2 + [631] ground states in these two nuclei. These differences mirror those observed in the even–even Pu and U immediate neighbors and appear to be related to the strength of octupole correlations.

Deep-inelastic reactions between a beam of 1360 MeV 208Pb ions and a thick 238U target have been used to populate the neutron-rich nucleus 211Pb. The observation of its γ decay has allowed identification of excited states up to the highest spin which can be formed from the three valence neutrons, including identification of three high-spin isomers. Level energies and transition strengths are compared to shell-model calculations with empirical interactions and predictions are made for the expected behaviour of more neutron-rich lead isotopes. The evidence for a possible increase in the neutron effective charge moving away from the N = 126 shell gap is evaluated.

Particle gamma-ray angular correlation measurements have been used to study the spin alignment and magnetic-substate population parameters for the 2 + 1 (4.443 MeV) state in 12 C, populated in the 12 C ( 12 C , 12 C [0 + 2 ]) 12 C (2 + 1 ) inelastic scattering reaction in the vicinity of a prominent, narrow peak in the scattering excitation function. The data show a strong alignment of the spin with the orbital angular momentum, and suggest that the cross section peak corresponds to a spin 14 + resonance at E c.m. =28.0 MeV. This energy is close to that where a strong peak is also observed in the 0 + 1 +0 + 2 excitation function. A comparison between the data for these two channels lends some support to recent theoretical calculations of resonance behavior for angular-momentum-mismatched channels in 12 C + 12 C inelastic scattering.

Entry distributions in angular momentum and excitation energy have been measured for several very proton-rich isotopes of Pt and Au. This is the first systematic study of the energy-spin phase space for nuclei near and beyond the proton drip line. Comparisons are made between the distributions associated with proton-unbound Au nuclei and more stable Pt isobars. In 173 Au the first evidence is seen for the limits of excitation energy and angular momentum which a nucleus beyond the proton drip line can sustain.

The level structure of 5422Ti32 has been explored for the first time by combining β-decay measurements from fragmentation products with prompt γ-ray spectroscopy following deep inelastic reactions. The latter technique was also instrumental in tracing 52Ti30 to higher spin. The data provide new tests of effective interactions for full pf-shell calculations in neutron-rich nuclei above 48Ca. The data indicate the presence of a significant subshell gap at N=32 and comparisons between theory and experiment suggest an additional shell closure at N=34 in Ca and Ti isotopes.

Excited states in the proton-unbound 173,175,177 Au nuclei were identified for the first time. Level structures associated with three different shapes were observed in 175 Au. While the yrast lines of 175 Au and 177 Au consist of a prolate band built upon the intruder 1/2 + [660] ( i 13/2 ) proton orbital, no sign of collectivity was observed in the lighter 173 Au isotope. Implications for the deformation associated with these structures are discussed with a focus on shape co-existence in the vicinity of the proton-drip line.

Three superdeformed (SD) bands have been found in 168Hf. Lifetime measurements revealed a large quadrupole moment, Q t ∼11.4 e b , for the strongest band (TSD1). Theoretical calculations using the Ultimate Cranker code predict high-spin SD minima (ϵ2∼0.43) with stable triaxial deformations of γ∼+20° and γ∼−15°. The measured Qt value suggests that band TSD1 corresponds, most likely, to a deformation with a positive γ value. This constitutes the first evidence for triaxial superdeformation in an even proton system.

The E1 response of the semi-magic nucleus 140Ce below the particle threshold was measured in a (γ,γ′) experiment utilizing the new Euroball Cluster detector at the S-DALINAC. While the energy averaged data are in good agreement with tagged photon results, here they are resolved for the first time into 54 individual transitions. A quasiparticle-phonon model calculation including up to three-phonon configurations compares well to the extracted strength distribution. The interference between one- and two-phonon contributions is essential for a quantitative reproduction.

The low spin structure of 130Ba was investigated via the emitted γ-radiation following the β-decay of 130La. New “K = 0”- and “K = 4”- bands were identified. A comparison with the O(6) symmetry of the IBM is shown. A discussion of the low lying levels of the O(6) symmetry in terms of multiple quadrupole “phonon” excitations built on the ground state is given.

A nuclear resonance fluorescence experiment with two highly efficient EUROBALL Cluster detectors has been performed on the γ -soft nucleus 194 Pt. Dipole excitations were observed between 2 and 4 MeV excitation energy. They are tentatively interpreted as the main fragments of the scissors mode based on the measured excitation strengths and a comparison to microscopic calculations in the framework of the quasiparticle random phase approximation (QRPA). The data indicate large differences to the neighbouring isotope 196 Pt: a doubling of the observed dipole strength and a shift of the energy centroid by about 600 keV. None of the currently available models is able to reproduce these features consistently in both nuclei.

High spin states in 167 Lu were populated through the 123 Sb( 48 Ca, xn ) reaction at 203 MeV. Four, presumably triaxial, strongly deformed (TSD) bands have been found in this nucleus. Several transitions linking an excited TSD band (TSD2) to the lowest (yrast) TSD band (TSD1) were observed. The electromagnetic properties of the connecting transitions have been investigated. Evidence for the assignment of TSD2 as a wobbling mode built on TSD1 is presented. This assignment is based on comparisons of the experimental data to theoretical calculations. The wobbling mode of excitation is an unambiguous signal of a stable triaxial deformation associated with these bands.

Excited structures in the neutron-deficient nucleus 179 Hg have been established for the first time using the Gammasphere spectrometer in conjunction with the fragment mass analyzer. Competing states originating from three different minima associated with nearly spherical, oblate, and prolate deformations were found. This result can be contrasted with the situation in heavier odd-mass Hg isotopes where only two minima (oblate and prolate) have been seen. The implications of these three shapes at low spin and excitation energy are discussed in the general context of shape coexistence in this mass region.

Three, possibly four, regularly spaced rotational bands with large dynamic moments of inertia have been identified in 174 Hf. Their properties are consistent with known triaxial superdeformed bands of the Lu/Hf region. Calculations predict substantial triaxial deformation ( γ ≈±17°) for 174 Hf structures with deformation ϵ 2 ≈0.45, despite the fact that 174 Hf is eight neutrons away from the previously established N =94 triaxial superdeformed gap. Shell gaps at N =100 and 106 with γ ⩾15° are predicted for ϵ 2 ≈0.45, and are most likely responsible for the calculated TSD minima in 174 Hf.