1206.6773 (C. Özen et al.)

The crossover from vibrational to rotational collectivity in heavy
nuclei in the shell-model Monte Carlo approach    [PDF]

C. Özen, Y. Alhassid, H. Nakada

We use the shell-model Monte Carlo approach to study microscopically the crossover from vibrational to rotational collectivity in families of even-even samarium and neodymium isotopes. In particular, we identify a signature of this crossover in the low-temperature behavior of $<\mathbf{J}^2>_T$, where $\bf J$ is the total spin and $T$ is the temperature, and find it in agreement with its values inferred from experimental data. We calculate the state densities and find them to agree very well with experimental data. We also calculate a collective enhancement factor from the ratio of the total state density to the intrinsic state density as calculated in the finite-temperature Hartree-Fock-Bogoliubov approximation. The decay of this enhancement factor with excitation energy is shown to be correlated with the pairing and shape phase transitions in these nuclei.

View original: http://arxiv.org/abs/1206.6773