A Simple Systematical Law of E2＋ Values for Heavy Nuclei in the NpNn Scheme and the Evolution of the Z=64 Shell Gap  

作　　者：樊哲勇 任中洲 许昌 

机构地区：[1]Department of Physics, Nanjing University, Nanjing 210008 [2]Center of Theoretical Nuclear Physics, National Laboratory of Heavy-Ion Accelerator, Lanzhou 730000

出　　处：《Chinese Physics Letters》2007年第9期2555-2558,共4页中国物理快报（英文版）

基　　金：Supported by the National Natural Science Foundation of China under Grant No 10535010. Z. Ren thanks Professor Y. M. Zhao for discussion.

摘　　要：A systematics of excitation energy of the first 2^＋ state E2＋ in even-even heavy nuclei （A ≥ 120） is studied in the NpNn scheme. It is found that a simple exponential function describes the dependence of E2＋ values on NpNn values very well. In addition, the Z = 64 shell gap is reexamined by investigating the systematics of the 52 ≤ Z ≤66 region. It is found that the Z = 64 shell gap is largest at N = 82 and becomes smMler with either increasing or decreasing of neutron numbers. The effects of this shell gap become negligible for counting the valence proton numbers when N ≥ 92 or N ≤ 72.A systematics of excitation energy of the first 2^＋ state E2＋ in even-even heavy nuclei （A ≥ 120） is studied in the NpNn scheme. It is found that a simple exponential function describes the dependence of E2＋ values on NpNn values very well. In addition, the Z = 64 shell gap is reexamined by investigating the systematics of the 52 ≤ Z ≤66 region. It is found that the Z = 64 shell gap is largest at N = 82 and becomes smMler with either increasing or decreasing of neutron numbers. The effects of this shell gap become negligible for counting the valence proton numbers when N ≥ 92 or N ≤ 72.

分 类 号：O57[理学—粒子物理与原子核物理]