Analysis of clustering fragments of ${}^7$Li and ${}^7$Be in the microscopic cluster model

Abstract

The nuclear structures of ${}^7$Li($\hat{I}\pm +n+n+p$) and ${}^7$Be($\hat{I}\pm +p+p+n$) are studied within the microscopic cluster model, in which the clustering fragments e.g., triton, ${}^3$He, and even the single nucleons around the core are studied in the ${}^7$Li and ${}^7$Be systems. We obtain the energy spectra and wave functions of ${}^7$Li and ${}^7$Be, and the calculated energy spectra of the ground states and some of the excited states are consistent with experimental data. To investigate the cluster-formation probabilities, we calculate the reduced-width amplitudes of various binary partitions. The results show that the $\hat{I}\pm +t{(}^3\mathrm{He})$ cluster structure is dominant in the low-lying states of ${}^7$Li(${}^7$Be), including the ground state and the three lowest excited states. In some higher states around the single-particle thresholds, the components of $\mathrm{core}+N$ structures, namely ${}^6\mathrm{Li}+n$ and ${}^6\mathrm{He}+p$ in ${}^7$Li and ${}^6\mathrm{Li}+p$ in ${}^7$Be, are significantly enhanced.

11 pages, 5 figures