Two-alpha-particle-plus-dinucleon-cluster model for10B and10Be

Abstract

The nuclei 10Be and 10B are investigated in the framework of the two-alpha-particle-plus-dinucleon-cluster model. The Pauli exclusion principle for the nucleons is taken into account using the orthogonality condition model. Almost all of the level energies up to an excitation energy of 7.5 MeV for both parity states with isospin T=0 or 1 are reproduced. Low-lying positive-parity states have a compact structure; on the other hand, negative-parity states have a weakly bound cluster structure. Calculated mu moments and M1 transition rates are in agreement with the observed data. Calculated Q moments and E2 transition rates are smaller than the observed data; however, the general tendency of the data is reproduced by including an effective charge. The 1+, T=0 (5.18 MeV) and the O+, T=1(7.56 MeV) states of 10B have not been explained by any other models. The present cluster model reproduces the excitation energies of these states and shows that they have a well developed cluster structure. Some other states near the three-cluster threshold energy are also predicted to have a well developed cluster structure.