Speaker
Description
On the base of microscopic version of the IBM1 plus other bosons
of positive parity with spins from $0^+$ to $10^+$ properties of
yrast-band states in even Ce isotopes are studied. Parameters of
the boson Hamiltonian and interactions of the collective
quadrupole bosons with other bosons are calculated
microscopically. This study is a continuation of similar works on
the isotopes Xe and Ba [1], in which the possibilities of the
microscopic theory have been investigated in the description of
increasingly deformed nuclei.
In all considered even Ce isotopes in which there are developed
yrast-bands theoretical calculations show that at spin $I{\rm
cr}=12^+$ in $^{122-128}$Ce and at $I{\rm cr}=10^+$ in
$^{130,132}$Ce the band-crossing takes place just as in even Ba
isotopes [1]. The back-bending in moment of inertia (expect
$^{122}$Ce) at corresponding rotational frequency and minima in
$B(E2;\ I\rightarrow I-2)$ values at $I=I{\rm cr}$ serve
experimental confirmation of such calculations. In $^{122}$Ce
because of a strong interaction between two bands the moment of
inertia up to $I=14^+$ retains the square dependence on frequency.
The suggested theory satisfactory describes these experimental
facts: fig.1 present yrast-band energies (theoretical quantities
distinguish from experimental ones not more then by 60 keV), fig.2
$B(E2)$'s for $^{128}$Ce.
- A.D.Efimov,V.M.Mikhajlov//Bull.RAS.Ac.Sci.Phys.2018.V.82.P.1266;
ibid.2019.V.83.P.113.
