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 resultwas identification of several nuclei as new magic
ones. Namely, itwas found that a filling of the neutron 2
d
5/2 subshell in
96Zr 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 2
p
1/2 and empty 1
g
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
96Zr. Therefore,
96Zr was identified as a new double-magic nucleus. Further investigations revealed that the energy of the first 2
+ state
E(2
1
+
) in
96Zr is much higher than that in the neighboring isotopes and isotones, whereas the ratio
E(4
1
+
)/
E(2
1
+
) and the quadrupole deformation parameter β2 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.
π1
f
5/2 and
ν2
d
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,
π2
p
1/2, occurs above the proton
π1
f
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:
54Ca (closed
π1
d
3/2 and
ν2
p
3/2 together with closed
ν2
p
1/2),
30S and
30Si (closed
π1
d
5/2 and
ν1
d
5/2 together with closed (
π/ν)2
s
1/2), and
14O and
14C (closed
π1
p
3/2 and
ν1
p
3/2 together with closed
ν2
p
1/2).
The text was submitted by the authors in English.
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