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Abstract: Excited states in 57Cr have been populated to high spin in the reaction at a beam energy of 130 MeV. A regular sequence of stretched quadrupole transitions has been established above the yrast level. This sequence is interpreted as a rotational band associated with prolate deformation induced by the excitation of the odd neutron into the orbital. Total Routhian surface calculations, which follow this configuration to high spin, reproduce the observed features of the band. They are also able to account for a similar, but less well developed structure in 55Cr. In contrast, the isomeric yrast state in 59Cr appears to be a band-head state dominated by the configuration, which is favoured at oblate deformations. Such a marked difference presents a significant challenge for theoretical descriptions, but is consistent with features exhibited by the low-lying negative-parity states in 59Cr. [Copyright &y& Elsevier]

Abstract: The level structures of 55V and 55Ti, the two nuclei with a single nucleon outside the semi-magic 54 22Ti32 core, have been investigated in order to provide new tests of full pf-shell calculations with the GXPF1A interaction. The addition of a proton does not appear to affect the shell gap significantly, although comparisons between calculations and experiment at high spins () indicate the need for a larger model space for an accurate description of the data in this regime. The energy separation between the and orbitals in neutron-rich Ti isotopes is not large enough to result in an shell gap. However, comparisons between the 55Ti data and the calculations argue for the presence of a sizable gap in 54Ca. [Copyright &y& Elsevier]

Abstract: Excited states up to in the neutron-rich nucleus 58Cr have been identified by using a new experimental setup composed of the large acceptance magnetic spectrometer PRISMA and the highly efficient γ-detector array CLARA. Interestingly, the excitation energy sequence of the ground-state band follows the one expected by the dynamical symmetry for a nucleus at the critical point of the shape phase transition from a spherical vibrator () to a γ-soft rotor (). For the first time, in the same physical system, large scale shell-model calculations in the full fp shell are compared to the analytical model results and to the Interacting Boson Model. The theoretical results are in excellent agreement with the present data. [Copyright &y& Elsevier]

Abstract: A study of high spin states in the odd-neutron isotones 239Pu and 237U is reported. Striking differences were found in the high-spin properties of rotational bands built on the 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. [Copyright &y& Elsevier]