质子-中子相互作用与壳模型配对近似

Proton-neutron interactions and nucleon-pair approximation

质子-中子相互作用和质子-中子配对是原子核结构中有趣的问题。本文指出,经验上由结合能提取的质子-中子相互作用和壳模型计算得到的T=0质子-中子相互作用的计算结果很接近;计算中奇奇核和偶偶核的结合能应该附加一个额外项,这个额外项由质子-中子相互作用给出。自旋平行的质子-中子配对(角动量为9,同位旋为0)在96Cd的01+、21+、41+、61+、121+、141+和161+态以及92Pd原子核的01+和21+态中重要,而传统的SD配对近似对于01+和21+态的描述更合适。

Background： Nucleon-pair correlations play an important role in low-lying states of atomic nuclei. Purpose： The aim is to study empirical proton-neutron interactions and investigate the contribution from spin-aligned proton-neutron pairs （with spin 9 and isospin 0） in low-lying states of ^96Cd and ^92pd. Methods： The empirical proton-neutron interaction is obtained by using nuclear binding energies of a few neighboring nuclei and the nuclear shell model. The contribution from spin-aligned proton-neutron pairs in the shell model wave functions is evaluated by using the nucleon-pair approximation with isospin symmetry. Results： The empirical proton-neutron interaction is reasonably consistent with isoscalar interactions calculated by using the shell model. There exists an additional binding energy in both even-even and odd-odd nuclei originated from proton-neutron interactions. Spin-aligned isoscalar pairs play an important role in the 01^＋, 2^＋, 41^＋, 61^＋, 121^＋, 141^＋ and 161^＋ states of ^96Cdandthe 01^＋, 21^＋ states of ^92pd. For the 01^＋ and 21^＋ states, the conventional isovector SD pairs are more relevant. Conclusion： Both isoscalar and isovector nucleon pairs play an important role in low-lying states of N=Z nuclei. This is a consequence of nonorthogonality feature of nucleon-pair basis.