Nuclear-resonance-fluorescence spectra have been measured in the chain of l48l50 ' 152154 Sm isotopes. Together with supplementary information from inelastic electron scattering and other reaction studies, orbital Ml transition strengths have been deduced from a number of 1 + states located around an excitation energy of 3 MeV. The systematic study, carried out for the first time, for nuclei within a large range of the deformation parameter 8 shows that the orbital Ml strength varies quadratically with 8. This result is interpreted in terms of models containing explicitly neutron and proton degrees of freedom.PACS numbers: 21.10. Re, 23.20.Qz, 25.20.Dc, 27.70.+q The role of neutron-proton interactions on collective nuclear excitations has been a subject of investigations for over four decades. Soon after the discovery of giant dipole resonances, they were interpreted 1 as isovector volume vibrations with neutrons as a whole oscillating out of phase against protons. More recently, a so-called "scissors mode" of oscillations based on a macroscopic two-rotor model (TRM) was suggested, 2 which predicts that 1 + levels with strong ground-state Ml transitions occur in even-even deformed nuclei. The discovery 3 of A/1 excitations in heavy deformed nuclei by highresolution inelastic electron scattering led to a series of detailed investigations on experimental and theoretical fronts. 4 These excitations today still constitute also the best proof for the so-called "mixed-symmetry states" in the neutron-proton interacting-boson model (IBM-2). 5 Macroscopic calculations predict that the orbital Ml strength is to be found in one or a few states, while the experiments indicate that it is generally fragmented into more levels (see, e.g., Refs. 4 and 6). This disparity with macroscopic descriptions is attributed to two-quasiparticle excitations. 7 Very recently, a systematic study 8 of Ml strength in the rare-earth region within the Nilsson model has shown quantitatively a direct correlation between the quadrupole ground-state deformation and the orbital magnetic dipole strength. This finding is also in agreement with predictions 5,9 of the interacting-boson model where in both the SU(3) and the 0(6) limits, i.e., the case where nonspherical nuclei rotate and vibrate, respectively, the reduced Ml transition strength is proportional to N X NJ(N X +N V ), with N K (N v ) being the number of valence proton (neutron) bosons, and is thus within a given series of isotopes not only a function of the number of neutrons present but predominantly dependent upon the neutron-proton interaction responsible for the quadrupole deformation of nuclear ground states. 10 Besides these two classes of models, other calculations exist where the deformation parameter 5 is explicitly contained in the analytic expressions for the reduced Ml transition strength. Some of them are random-phase-approximation predictions; 11 " 13 others re-sult from the TRM, sum-rule, and so-called giantangle-dipole approaches. 14 " 16 These predictions, which are listed...

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In this article, we present the application of bilinear and biquadratic extended FEM (XFEM) formulations to model weak discontinuities in magnetic and coupled magneto-mechanical boundary value problems. For properly resolving the location of curved interfaces and the discontinuous physical behaviour, the major part of the contribution is devoted to review and develop methods for level set representation of curved interfaces and numerical integration of the weak form in higher-order XFEM formulations. In order to reduce the complexity of the representation of curved interfaces, an element local approach that allows for an automated computation of the level set values and also improves the compatibility between the level set representation and the integration subdomains is proposed. Integration rules for polygons and strain smoothing are applied in conjunction with biquadratic elements and compared with curved integration subdomains. Eventually, a coupled magneto-mechanical demonstration problem is modelled and solved by XFEM. For demonstration purposes, a magneto-mechanical coupling due to magnetic stresses is considered. Errors and convergence rates are analysed for the different level set representations and numerical integration procedures as well as their dependence on the ratio of material parameters at an interface.

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Abstract. The 115In(~;, ~/') reaction was measured at the S-DALINAC using bremsstrahlung with endpoint energies Eo= 3.1, 4.6 and 5.2 MeV. In the excitation energy range of 1-5 MeV in total 32 transitions were observed, 18 of which were hitherto| unknown. The results are compared to two quasiparticle-phonon model calculations, one with a model space of'quasiparticle | and one extended by 'quasiparticle| configurations. A substantial improvement is achieved in the description of low-lying ~SIn states by the consideration of the more complex configurations. The calculations quantitatively account for the summed l~SIn(~, 7') integrated cross sections and show a comparable amount of fragmentation of the individual transition strengths. The model interpretation of the microscopic structure of the experimentally observed transitions is discussed.