Nuclear Techniques ›› 2014, Vol. 37 ›› Issue (10): 100502-100502.doi: 10.11889/j.0253-3219.2014.hjs.37.100502

• NUCLEAR PHYSICS, INTERDISCIPLINARY RESEARCH • Previous Articles     Next Articles

Proton-neutron interactions and nucleon-pair approximation

FU Guanjian ZHAO Yumin   

  1. (Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China)
  • Received:2014-04-30 Revised:2014-05-28 Online:2014-10-10 Published:2014-10-16

Abstract:

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+ , 21+ , 41+ , 61+ ,  121+,  141+and 161+ states of 96Cd and the 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.

Key words: Proton-neutron interaction, T=0 proton-neutron pair, Nucleon-pair approximation