arXiv subjects

T. Nikši\' c

Publications and source records attributed to T. Nikši\' c.

3 recordsLinked to original sources

arXiv2025

Microscopic model for yields and total kinetic energy in nuclear fission

An extension of time-dependent density functional theory (TDDFT), the generalized time-dependent generator coordinate method (TDGCM), is applied to a study of induced nuclear fission dynamics. In the generalized TDGCM, the correlated nuclear wave function is represented as a coherent superposition of time-dependent DFT trajectories. In the first realistic application, a large basis of 25 TDDFT trajectories is employed to calculate the charge yields and total kinetic energy distribution for the fission of $^{240}$Pu. The results are compared with available data, and with those obtained using a standard TDDFT, that does not consider quantum fluctuations, and the adiabatic TDGCM+GOA (Gaussian overlap approximation). It is shown that fragment yields and kinetic energies can simultaneously be described in a consistent microscopic framework that includes fluctuations in the collective degrees of freedom and the one-body dissipation mechanism.

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arXiv2018

Shape evolution and coexistence in neutron-deficient Nd and Sm nuclei

The evolution of shapes and low-energy shape coexistence is analyzed in neutron-deficient Nd and Sm nuclei, using a five-dimensional quadrupole collective Hamiltonian (5DCH). Deformation energy surfaces, calculated with the relativistic energy density functional PC-PK1 and a separable finite-range pairing interaction, exhibit a transition from spherical shapes near $N=80$, to $γ-$soft shapes, and to prolate deformed minima in lighter isotopes. The corresponding 5DCH model calculation, based on the self-consistent mean-field potentials, reproduces the empirical isotopic trend of characteristic collective observables, and predicts significantly different deformations for the first two $0^+$ states in the $N=74$ isotones $^{134}$Nd and $^{136}$Sm. In addition to bands based on the triaxial $γ-$soft ground state, in excellent agreement with data, the occurrence of a low-energy rotational band is predicted, built on the prolate deformed ($β\sim0.4$) excited state $0^+_2$.

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arXiv2008

Bubbles in $^{34}$Si and $^{22}$O?

Bubble nuclei are characterized by a depletion of their central density. Their existence is examined within three different theoretical frameworks: the shell model as well as non-relativistic and relativistic microscopic mean-field approaches. We propose $^{34}$Si and $^{22}$O as possible candidates for proton and neutron bubble nuclei, respectively. In the case of $^{22}$O, we observe a significant model dependence, thereby calling into question the bubble structure of $^{22}$O. In contrast, an overall agreement among the models is obtained for $^{34}$Si. Indeed, all models predict a central proton density depletion of about 40%. This result provides strong evidence in favor of a proton bubble in $^{34}$Si.

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