The nonyrast states of Xe-124 have been investigated with the Te-123(He-3, 2n) reaction by means of in-beam gamma -spectroscopy using a setup of 6 Compton-suppressed high-purity-germanium (HPGe) detectors. More than 65 new transitions, establishing 34 new levels, were observed, gamma gamma -angular correlations were analyzed to assign spins and parities to the low-lying states, and to determine the multipolarities of the gamma -transitions. In addition, the gamma -excitation-function method was used for spin assignments. With these methods 10 (18) spin and parity assignments were made (some of them tentative) and 7 multipole mixing ratios could be determined. The excitation energies and B(E2) ratios of low-lying states are compared with predictions of the sd-IBM-1, giving rise to the identification of a 0(+) state with O(6) quantum number sigma = N - 2, Quadrupole shape invariants for the ground state and effective deformation parameters are calculated, showing an admixture of U(5) symmetry to the ground-state wave function. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 35]
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