Level density of odd-A nuclei at saddle point

摘要: Based on the covariant density functional theory, by employing the core--quasiparticle coupling (CQC) model, the nuclear level density of odd-$A$ nuclei at the saddle point is achieved. The total level density is calculated via convolution of the intrinsic level density and the collective level density.
The intrinsic level densities are obtained in the finite-temperature covariant density functional theory, which takes into account the nuclear deformation and pairing self-consistently. For saddle points on the free energy surface in the $(\beta_2, \gamma)$ plane, the entropy and the associated intrinsic level density are compared with those of the global minima. By introducing a quasiparticle to the two neighboring even--even core nuclei, whose properties are determined by the five-dimensional collective Hamiltonian model, the collective levels of the odd-$A$ nuclei are obtained via the CQC model. The total level densities of the $^{234-240}$U agree well with the available experimental data and Hilaire's result.
Furthermore, the ratio of the total level densities at the saddle points to those at the global minima and the ratio of the total level densities to the intrinsic level densities are discussed separately.