New double-magic nucleus {sup 96}Zr and conditions for existence of new magic nuclei

Journal Article · Wed Aug 15 04:00:00 EDT 2007 · Physics of Atomic Nuclei

DOI:https://doi.org/10.1134/S1063778807080078· OSTI ID:21075754

Varlamov, V V; Ishkhanov, B S; Romanovsky, E A ^[1]

---

1. Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

New information about energies and occupation probabilities of neutron and proton single-particle (hole) subshells in even-even nuclei was obtained in previous studies applying the method of putting into correspondence all available data on one-nucleon pickup and stripping reactions. The most important and interesting result was identification of several nuclei as new magic ones. Namely, itwas found that a filling of the neutron 2d{sub 5/2} subshell in {sup 96}Zr makes this nuclide a magic one. Moreover, changes in proton subshell energies with increasing neutron number N are accompanied by an increasing energy gap between closed 2p{sub 1/2} and empty 1g{sub 9/2} subshells. Thus, the neutron number N = 56 appears to be a magic one if the proton number Z is equal to 40. The proton number Z = 40 manifests properties of the magic number in {sup 96}Zr. Therefore, {sup 96}Zr was identified as a new double-magic nucleus. Further investigations revealed that the energy of the first 2{sup +} state E(2{sub 1}{sup +}) in {sup 96}Zr is much higher than that in the neighboring isotopes and isotones, whereas the ratio E(4{sub 1}{sup +})/E(2{sub 1}{sup +}) and the quadrupole deformation parameter {beta}2 are, vice versa, clearly lower. Moreover, the A dependence of the neutron separation energy B(n) in Zr isotopes has an irregularity at N = 56 which is typical of magic nuclei. As a result of these investigations, it was found that, near the Fermi energy, there are two closed subshells with the same (and large) angular momentum j 5/2 (viz. {pi}1f{sub 5/2} and {nu}2d{sub 5/2}). We call this situation the jj connection. The magic numbers under discussion (Z = 40 and N = 56) are achieved at the points where both subshells are closed, and in addition, the closed subshell with j = 1/2, {pi}2p{sub 1/2}, occurs above the proton {pi}1f{sub 5/2} subshell. This looks like a result of some additional attractive proton-neutron interaction. It was found that application of this scheme (jj connection) to other subshells reveals several other new magic nuclei: {sup 54}Ca (closed {pi}1d{sub 3/2} and {nu}2p{sub 3/2} together with closed {nu}2p{sub 1/2}), {sup 30}S and {sup 30}Si (closed {pi}1d{sub 5/2} and {nu}1d{sub 5/2} together with closed ({pi}/{nu})2s{sub 1/2}), and {sup 14}O and {sup 14}C (closed {pi}1p{sub 3/2} and {nu}1p{sub 3/2} together with closed {nu}2p{sub 1/2})

• OSTI ID: 21075754
• Journal Information: Physics of Atomic Nuclei, Journal Name: Physics of Atomic Nuclei Journal Issue: 8 Vol. 70; ISSN 1063-7788; ISSN PANUEO
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR MOMENTUM
CALCIUM ISOTOPES
CARBON 14
DEFORMATION
ENERGY GAP
EVEN-EVEN NUCLEI
ISOTONIC NUCLEI
MAGIC NUCLEI
NEUTRON SEPARATION ENERGY
NEUTRONS
OXYGEN 14
PROTON-NEUTRON INTERACTIONS
PROTONS
QUADRUPOLES
SILICON 30
STRIPPING
ZIRCONIUM 96