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The semimicroscopic algebraic cluster model (SACM) is applied to the systems 12C + α -> 160, 14C + α -> 180, 160 + α-> 20Ne, 18C + α -» 22Ne, and 20Ne + α -* 24Mg. The spectrum and some £2 values are fitted to experiment. Further E2 transition values as well as Ε1 and M1 transitions are calculated and compared to experiment. In addition, we list the spectroscopic factors of the states listed. These factors are predictions of the model and are of interest in current astrophysical studies. [ABSTRACT FROM AUTHOR]

Existing experimental data on elastic and inelastic deuteron scattering on Li nuclei in the energy range from 8 to 50 MeV were analyzed within the approach of coupled reaction channels. The coupling of elastic scattering and inelastic scattering accompanied by the transition to the 3 state at E = 2.186 MeV and the mechanism involving the exchange of an alpha-particle cluster were taken into account in respective calculations. The phenomenological potentials obtained from the present analysis describe well experimental angular distributions at all energies and in full angular ranges. The depths of the real and imaginary parts of the potentials in question depend smoothly on energy at fixed values of the remaining parameters. The energy dependence of relevant volume integrals agrees well with similar data for the p + Li, α + Li, and C + C systems and with the predictions of a microscopic theory. [ABSTRACT FROM AUTHOR]

Within the potential cluster model where orbital states are classified according to Young diagrams and isospin, astrophysical S factors are considered for radiative proton capture by H and Li nuclei at energies of up to 1 and 10 keV, respectively. It is shown that the approach used, which takes into account only the E1 transition for the pH capture process, makes it possible to describe well the most recent experimental data at c.m. energies in the range from 50 keV to 5MeV. In the case of proton capture by Li nuclei, an M1 processwas taken into account in addition to the E1 transition, and a general behavior and the magnitude of the experimental S factor could be correctly reproduced owing to this at astrophysical energies, including the region around the resonance at 0.441 MeV (in the laboratory frame). [ABSTRACT FROM AUTHOR]

How a complex network is connected crucially impacts its dynamics and function. Percolation, the transition to extensive connectedness on gradual addition of links, was long believed to be continuous, but recent numerical evidence of 'explosive percolation' suggests that it might also be discontinuous if links compete for addition. Here we analyse the microscopic mechanisms underlying discontinuous percolation processes and reveal a strong impact of single-link additions. We show that in generic competitive percolation processes, including those showing explosive percolation, single links do not induce a discontinuous gap in the largest cluster size in the thermodynamic limit. Nevertheless, our results highlight that for large finite systems single links may still induce substantial gaps, because gap sizes scale weakly algebraically with system size. Several essentially macroscopic clusters coexist immediately before the transition, announcing discontinuous percolation. These results explain how single links may drastically change macroscopic connectivity in networks where links add competitively. [ABSTRACT FROM AUTHOR]

Cross sections for 13C(α,α′) reactions at Eα = 400 MeV have been measured to obtain the monopole and quadrupole transition strengths. The excitation strengths are compared with the shell-model predictions. It is suggested that the large monopole strengths observed for the $1/2^-_2$ and $1/2^-_3$ states in 13C are attributed to the cluster structure of those states. [ABSTRACT FROM AUTHOR]

The newly developed generalized density-dependent cluster model is employed to study the favored a transitions of exotic nuclei in both ground and isomeric states. We perform a systematic calculation for the ground and isomeric states of neutron-deficient isotopes ranging from Z = 67 to Z = 89. No adjustable parameter is introduced in our calculation. The theoretical a-decay half-lives are found to be in good agreement with the experimental data. This indicates that a unified description of a-decay half-lives for both ground and isomeric states is achieved by our model. [ABSTRACT FROM AUTHOR]