Review of the nuclear systematics for nuclei ?≈140−214

Abstract

The excitation energies of lowest-lying spin/parity Iπ = 2+ nuclei states and ratio of first spin/parity 4+ to 2+ states, R(4/2) = E(4+)/E(2+)have been used to investigate the systematics of shape evolution with changing nucleon number which have been used to describe the degree of nuclei collectivity in heavy even-even nuclei for A ≈ 140-214. The review showedhigh excitation energy values ofyrast 2+ states near magic numbers of nucleons. The scattered points of isotopes of Po and Pb around N ≈ 96 – 126 and the magic numbersN = 82 and 126 whereR(4/2)< 2 is consistent with spherically shaped nuclei. The nuclei around R(4/2) ≈ 2.00 are consistent with quadrupole vibrational excitations about near-spherical nuclei which implied oblate shaped nuclei. Nuclei with N ≈ 90 – 96 where R(4/2≈ 2.5 agreed with? - soft rotor. The clustering of points around values of R(4/2)≈ 3.33 with N = 96 – 114 showed consistency with the perfect, axially symmetric quantum rotor nuclei with well deformed prolate shape. It is concluded that the nuclei with R(4/2)≈ 3.33 around N ≈ 96 – 114, would generate higher energy when used inthe production of betavoltaics and in nuclear power plants due to the ease in ?−-decay. On the other hand,nuclei with R(4/2)< 2 can easily be studied in the laboratory due to longer half-lives but may require larger amount of energy for nuclear synthesis due to closed shell and higher stability.

Keywords: Exotic nuclei, Shape evolution, Quadrupole deformation, Nuclei Stability.