Multicluster study of the C-12+n and C-12+p systems

We use the generator coordinate method to study the C-12(n, gamma)C-13 and C-12(p, gamma)N-13 reactions, as well as the C-13 and N-13 spectroscopy. The C-12 wavefunctions are defined by three alpha particles in a regular triangle of size R-C. Different configurations are considered, in order to analyze clustering effects. It is shown that spectroscopic properties of C-13 and N-13 are sensitive to the C-12 wave function; reasonable agreement with experiment is found with R-C values minimizing the C-12 binding energy. The present study supports the suggestion of a halo structure for the 1/2(+) excited state in C-13. The neutron and proton capture cross sections are in good agreement with experiment. Finally, we analyze distortion effects in the C-12+n wave functions.