Shell-model configuration-interaction description of quadrupole collectivity in Te isotopes

Systematic calculations on the spectroscopy and transition properties of even-even Te isotopes are carried out by using the large-scale shell-model configuration-interaction approach with a realistic interaction. These nuclei are of particular interest since their yrast spectra show a vibrational-like equally spaced pattern whereas the few known $E2$ transitions show rotational-like behavior. This cannot be explained by available collective models. My calculations reproduce well the equally spaced spectra of those isotopes as well as the constant behavior for the $B\left(E2\right)$ values of ${}^{114}\mathrm{Te}$. The calculated $B\left(E2\right)$ values of neutron-deficient and heavier Te isotopes show contrasting different behaviors along the yrast line. The $B\left(E2\right)$ of light isotopes can exhibit a nearly constant behavior up to high spins. It is shown that this is related to the enhanced neutron-proton correlation when approaching $N=50$.

Figure 1

Comparison between theory and experiment for the yrast spectra of the Te isotopic chain.

Figure 2

Comparison between theory and experiment for the energies of the $2^{+}$ and $4^{+}$ yrast states (upper) and the $B(E2;2_1{}^{+}\to 0_1{}^{+})$ values (middle) for the Te isotopic chain. The open circles and open triangles in the lower panel correspond to the neutron and proton matrix elements, $M_n$ and $M_p$, respectively.

Figure 3

Comparison between theory and experiment [29] for $B(E2;I_1{}^{+}\to {(I-2)}_1{}^{+})$ values in ${}^{114}\mathrm{Te}$ along the yrast line. The dashed lines correspond to the predictions of collective models [29].

Figure 4

Calculated $B[E2;I_1{}^{+}\to {(I-2)}_1{}^{+}]$ values along the yrast line for even-even Te isotopes.