COLLECTIVE STATES AND BANDCROSSING IN EVEN CERIUM ISOTOPES

13 Oct 2020, 17:00
25m
Online

Online

Oral report Section 1. Experimental and theoretical studies of the properties of atomic nuclei. Section 1. Experimental and theoretical studies of the properties of atomic nuclei

Speaker

Dr Alexander Efimov (Admiral Makarov State University of Maritime and Inland Shipping)

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.

  1. A.D.Efimov,V.M.Mikhajlov//Bull.RAS.Ac.Sci.Phys.2018.V.82.P.1266;
    ibid.2019.V.83.P.113.

Primary author

Dr Alexander Efimov (Admiral Makarov State University of Maritime and Inland Shipping)

Presentation materials