Research Information System
6th International Conference of the Balkan-Physical-Union, İstanbul, Turkey, 22 - 26 August 2006, vol.899, pp.117-118
Empirical values of the average interactions of the last two protons and last two neutrons, delta V-pn, which can be obtained from double differences of binding energies, provide significant information about nuclear structure. Studies of delta V-pn showed striking behavior across major shell gaps and the relation of proton-neutron (p-n) interaction strengths to the increasing collectivity and onset of deformation in nuclei. Here we focus on the strong regularity at the delta V-pn values in A similar to 150-180 mass region. Experimentally, for each nucleus, the valence p-n interaction strengths increase systematically against the neutron number and it decreases for the observed last neutron number. These experimental results give almost nearly perfect parallel trajectories. A microscopic interpretation with a zero range delta-interaction in a Nilsson basis gives reasonable agreement for Er-W but more significant discrepancies appear for Gd and Dy.