Microscopic calculations for Be isotopes within real-time evolution method
- PDF / 567,207 Bytes
- 5 Pages / 595.276 x 790.866 pts Page_size
- 59 Downloads / 168 Views
Regular Article - Theoretical Physics
Microscopic calculations for Be isotopes within real-time evolution method Bo Zhou1,2 , Masaaki Kimura2,3,a , Qing Zhao2,3 , Seung-heon Shin2 1
Institute for the Advancement of Higher Education, Hokkaido University, Sapporo 060-0817, Japan Department of Physics, Hokkaido University, 060-0810 Sapporo, Japan 3 Nuclear Reaction Data Centre, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
2
Received: 11 August 2020 / Accepted: 16 November 2020 © Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2020 Communicated by Cedric Simenel
Abstract The Be isotopes with α + α + valence neutrons clustering structure are studied within the Real-time Evolution Method (REM). By solving the equation-of-motion (EOM) of the Gaussian wave packets involving the complex spatial coordinates and spin variables, various molecular configurations are obtained and then are superposed in the Generator Coordinate Method (GCM). The obtained energy spectra from Be isotopes are better than those from other cluster models and also basically consistent with experiments. It is found the real-time evolution method provides us with an effective way to choose basis wave functions for dealing with the multi-neutron molecular structures of Be isotopes. The neutron-rich beryllium isotopes have been investigated by many nuclear models [1–5] due to their typical molecular structures. Experimental developments with RI beam also have extensively advanced the studies on beryllium isotopes. Microscopic cluster model can be considered as a useful tool for studying the well-known structure of α+α+valence neutrons in Be isotopes. Studies show that various molecular cluster states, e.g., the typical σ and π orbit structure, neutron-halo structure, shell-model-like structure could appear in the excited states of Be isotopes. For the low-lying states of the 12 Be, the possible breakdown of the N=8 shell closure has been reported [6,7], which has a close connection with the 0+ states at a low excitation energy. In Ref. [8], Ito et al. explored mechanism for quenching N=8 closure in the 12 Be nucleus from the viewpoint of the covalent molecular-orbit picture and the ionic He-cluster picture. Theoretically, to describe well these diverse molecular states, one key point is to include sufficient configurations for treating well the complex correlations between clusters or neutrons in the microscopic cluster model. However, with increase of the number of valence neutrons, a huge number of wave funca e-mail:
[email protected] (corresponding author)
0123456789().: V,-vol
tions with respect to the degrees of freedom involving the spatial coordinates and spin variables should be superposed, which leads to the expensive computations cost and is even unrealistic. To avoid the large-model space problem in GCM calculations, the idea from the Molecular Orbit (MO) method is, the motions for valence neutrons can be treated as linear combinations of orbits and these neutrons can
Data Loading...
