Angular momentum geometry of pseudospin partner bands in Cs 133

The pseudospin partner bands (labeled as bands 1 and 2) built on the configuration π(1g7/2,2d5/2)1 in Cs133 have been studied within the core-quasiparticle-coupling model, utilizing deformation parameters calculated from the relativistic density functional theory. The calculated energy spectra and electromagnetic transition probability ratios B(M1)/B(E2) agree well with experimental observations. An angular momentum coupling scheme relevant to these bands is deduced through investigations of the g factors, the static quadrupole moments, the probability distributions of the core angular momentum, the valence particle configuration components, the angle between particle and core angular momenta, and the individual angular momentum components. It is revealed that bands 1 and 2 are primarily based the 1g7/2 and 2d5/2 orbitals, with their respective core angular momentum values R approximately equal to I-7/2 and I-5/2, respectively. This results in a notable suppression of interband B(M1) transitions from band 1 to band 2, consistent with the observed near-zero B(M1)/B(E2) ratio.