arXiv subjects

T. Tretyakova

Publications and source records attributed to T. Tretyakova.

3 recordsLinked to original sources

arXiv2022

Seniority and $(\frac{9}{2})^n$ configurations in neutron-rich Nickel isotopes

Excited states in low-energy spectra in $^{70-76}$Ni are considered. To this end, pairing forces in form of surface delta interaction are employed to account for formation of the ground state multiplet with seniority $ν= 2$ states. The multiplet splitting is described with mass relations of masses of neighbouring nuclei. Subsequently, seniority model is used to reproduce or predict the states $ν= 3$ in odd-even isotopes and $ν= 4$ in even-even isotopes. Correct account of $2_1^+$ state should allow for description of reversed order of states $J = 4$ with $ν= 2$ and $ν= 4$ observed in experiment. The results obtained are compared with the structure of similar multiplets in $N=50$ isotones.

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arXiv2018

Empirical pairing gaps and neutron-proton correlations

Analysis of various mass relations connected with neutron-proton correlations in atomic nuclei is carried out. On the example of $N = Z$ chain it is shown that for self-adjoint nuclei various formulas proposed in literature for $ np $ pairing energy estimations lead to similar results. Significant differences between the calculation methods arise when nuclei with $N \ne Z$ are considered, which allows to show the complexity of neutron-proton correlations in different types of atomic nuclei and to make some assumptions on the correspondence of a mass ratio to the real effect of $ np $ pairing. The Shell Model parametrization of binding energy makes it possible to arrive to additional conclusions on the structure of mass formulas and their interrelationships with one another.

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arXiv2017

Evolution of single-particle structure of silicon isotopes

New data on proton and neutron single-particle energies $E_{nlj}$ of Si isotopes with neutron number $N$ from 12 to 28 as well as occupation probabilities $N_{nlj}$ of single particle states of stable isotopes $^{28,30}$Si near the Fermi energy were obtained by the joint evaluation of the stripping and pick-up reaction data and excited state decay schemes of neighboring nuclei. The evaluated data indicate following features of single-particle structure evolution: persistence of $Z = 14$ subshell closure with $N$ increase, the new magicity of the number $N = 16$, and the conservation of the magic properties of the number $N = 20$ in Si isotopic chain. The features were described by the dispersive optical model. The calculation also predicts the weakening of $N = 28$ shell closure and demonstrates evolution of bubble-like structure of the proton density distributions in neutron-rich Si isotopes.

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