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Excited states in 98Ru were investigated using γ-ray spectroscopy following the β-decay of 98Rh, and via the 100Ru( p , t ) reaction. Combining the results from the two experiments, two states were revised to have spin-parity of 4 + and subsequently assigned to the 0 2 + and “γ” bands, respectively. The observed structures in 98Ru are suggested to be deformed and rotational, rather than spherical and vibrational, and fit well into the systematics of these excitations in the Ru isotopes. The 0 2 + excitation is suggested as a shape coexisting configuration. This observation eliminates some of the last remaining candidates for nearly harmonic vibrational nuclei in the Z ≈ 50 region. Beyond-mean-field calculations are presented that support shape coexistence throughout the Ru isotopes with N = 52 –62, and suggest a smooth evolution of the shapes.

We study the low-lying energy spectrum of the rp -process waiting point nucleus Zr 80 with state-of-the-art beyond mean field methods with the Gogny D1S interaction. Symmetry restoration and configuration mixing of axial and triaxial shapes are included in the calculations. Five 0 + states corresponding to different nuclear shapes are obtained below 2.25 MeV and several rotational and γ -bands built upon them are identified. Nevertheless, these states do not modify the β -decay half-life having a negligible effect in the rp -process. A good agreement with the available experimental data is obtained.

The influence of large amplitude pairing fluctuations is investigated in the framework of beyond mean field symmetry conserving configuration mixing calculations. In the numerical application the finite range density dependent Gogny force is used. We investigate the nucleus $^{54}$Cr with particle number and angular momentum projected wave functions considering the axial quadrupole deformation and the pairing gap degree of freedom as generator coordinates. We find that the effects of the pairing fluctuations increase with the excitation energy and the angular momentum. The self-consistency in the determination of the basis states plays an important role., Comment: 9 pages, 5 figures

Recent experimental results obtained using β decay and isomer spectroscopy indicate an unusual behaviour of the energies of the first excited 2 + states in neutron-rich Cd isotopes approaching the N = 82 shell closure. To explain the unexpected trend, changes of the nuclear structure far-off stability have been suggested, namely a quenching of the N = 82 shell gap already in 130Cd, only two proton holes away from doubly magic 132Sn. We study the behaviour of the 2 + energies in the Cd isotopes from N = 50 to N = 82 , i.e. across the entire span of a major neutron shell using modern beyond mean field techniques and the Gogny force. We demonstrate that the observed low 2 + excitation energy in 128Cd close to the N = 82 shell closure is a consequence of the doubly magic character of this nucleus for oblate deformation favoring thereby prolate configurations rather than spherical ones.

The beyond mean field approximation combined with the Gogny interaction is used to analyze the spherical to prolate deformed shape transition in the Neodymium isotopic chain. The vibrator as well as the rotor limits are nicely reproduced while the transitional region is only qualitatively described probably due to the lack of triaxial correlations in the calculations. Our results do not support the interpretation of $^{150}$Nd as a critical point nucleus and question the interpretation of shape changes as nuclear shape phase transitions., Comment: 12 pages, 9 figures, accepted in Phys. Lett. B

Multilayer structures consisting of several alternated layers of SiGe and SiO 2 with thickness ranging from 2 or Si as well as the deposition of SiO 2 on Si show negligible incubation times. The deposition of SiO 2 on SiGe, however, exhibits an incubation time of several minutes, which would be related to the oxidation of the surface necessary for the SiO 2 deposition to start. In all cases the film thickness increases linearly with deposition time, thus allowing the growth rates to be determined. These data allow the deposition process of these very thin layers to be accurately controlled.

In many situations of interest amplitude modulation AFM is characterized by the coexistence of two solutions with different physical properties. Here, we compare the performance of those solutions in the imaging of cobalt nanoparticles. We show that imaging with the high amplitude solution implies an irreversible deformation of the nanoparticles while repeated imaging with the low solution does not produce noticeable changes in the nanoparticles. Theoretical simulations show that the maximum tip–surface force in the high amplitude solution is about 14 nN while in the low amplitude solution is about −4 nN. We attribute the differences in the high and low amplitude images to the differences in the exerted forces on the sample.

The behaviour of Ir implanted into Si during subsequent thermal processing has been studied using ion beam analysis and transmission electron microscopy. Si(1 0 0) samples preamorphized by Si implantation and subsequently implanted with Ir were used. After regrowth of the amorphized substrate region at 550 °C, the samples were further annealed in vacuum at temperatures in the 650–800 °C interval for 600 s using a rapid thermal annealing system. As crystallization takes place, Ir segregates towards the amorphous part of the sample, in such way that the Ir concentration profile is shifted almost rigidly without Ir losses. At intermediate temperatures (700–730 °C) the Ir-rich layer remains buried into the Si. At high temperatures (above 750 °C) the Ir-rich layer reaches the surface of the sample. Both, the movement of the Ir layer and the maximum concentration of Ir in the Si crystallized region are characterized and their dependence on the temperature analyzed.

The crystallization kinetics and film microstructure of poly-SiGe layers obtained by solid-phase crystallization of unimplanted, C and F-implanted amorphous SiGe films have been studied. After crystallization, the F and C implanted SiGe films show larger grain sizes, both in-plane and perpendicular to the surface of the sample, than the unimplanted SiGe films. Also, the (111) texture is strongly enhanced when compared to the unimplanted SiGe or Si films. The structure of the C implanted SiGe samples consists of a mixture of grains with well defined contour and a small number of quasi-dendritic grains. These samples also show a very low grain size dispersion.