摘要
Using an isobaric method,the symmetry-energy coefficient(asym)of a neutron-rich nucleus is obtained from experimental binding energies.The shell effects are shown in a^(*)_(sym)/A≡4asym/A of nuclei.A(sub)magic neutron magic number N=40 is suggested in a very neutron-rich nucleus,and a^(*)_(sym)/A of a nucleus is found to decrease when its mass increases.The a^(*)_(sym)/A of a very neutron-rich nucleus with large mass saturates.The volume-symmetry coefficients(b_(v))and surface-symmetry coefficients(b_(s))of a neutron-rich nucleus are extracted from a sym*/A by a correlation a^(*)_(sym)/A=bv/A-b s/A^(4/3).It is found that bv and bs decrease when the nucleus becomes more neutron-rich,and tend to saturate in the very neutron-rich nucleus.A linear correlation between b v and bs is obtained in nuclei with different neutron-excess I,and bv of I>7 nuclei is found to coincide with the results of infinite nuclear matter a sym=32±4 MeV,and bs/bv of the nucleus is found to coincide with the results of the finite-range liquid-drop model results.
作者
马春旺
杨聚宝
于勉
普洁
王闪闪
魏慧玲
MA Chun-Wang;YANG Ju-Bao;YU Mian;PU Jie;WANG Shan-Shan;WEI Hui-Ling(Department of Physics,Henan Normal University,Xinxiang 453007;Department of Life Sciences and Technology,Xinxiang Medical University,Xinxiang 453003;Department of Nuclear Physics,Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800)
基金
Supported by the National Natural Science Foundation of China under Grant No 10905017
the Program for Innovative Research Team in Science and Technology under Grant No 2010IRTSTHN002
the Universities of Henan Province,and the Young Teacher Project in Henan Normal University.