arXiv subjects

J. Skalski

Publications and source records attributed to J. Skalski.

23 records · Page 2Linked to original sources

arXiv2007

Relative motion correction to fission barriers

We discuss the effect of kinetic energy of the relative motion becoming spurious for separate fragments on the selfconsistent mean-field fission barriers. The treatment of the relative motion in the cluster model is contrasted with the necessity of a simpler and approximate approach in the mean-field theory. A scheme of the energy correction to the Hartree-Fock is proposed. The results obtained with the effective Skyrme interaction SLy6 show that the correction, previously estimated as $\sim$ 8 MeV in $A=70-100$ nuclei, amounts to 4 MeV in the medium heavy nucleus $^{198}$Hg and to null in $^{238}$U. However, the corrected barrier implies a shorter fission half-life of the latter nucleus. The same effect is expected to lower barriers for multipartition (i.e. ternary fission, etc) and make hyperdeformed minima less stable.

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arXiv2004

Adiabatic nucleus-nucleus potential at near-barrier energies from selfconsistent calculations

Adiabatic fusion potentials, extended well into compound nucleus region, are calculated for a number of reactions within the static Hartree-Fock method with the Skyrme SkM* interaction. The calculated fusion barriers agree quite well with the data, in spite of considerable errors in reaction Q values. This suggests some error cancellation, possibly with the relative kinetic energy term. Calculated berrier heights are consistent with the idea of fusion hindrance in tip collisions. Adiabatic potentials differ considerably from the results of the frozen density approximation. We briefly discuss relative positions and heights of the fusion and fission potentials and speculate on their possible connection with the fusion hindrance for large Zt Zp.

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arXiv1997

The excitation of a quantum gas of independent particles under periodic perturbation in integrable or non-integrable potential

The excitation of a quantum gas of 112 independent fermions in the time-dependent potential well, periodically oscillating around the spherical shape, was followed over 10 oscillation cycles. Five different oscillation frequencies are considered for each of the five types of deformations: spheroidal and Legendre polynomial ripples: P_3, P_4, P_5 and P_6. The excitation rate of the gas in the deforming hard-walled cavities substantially decreases after initial one or two cycles and the final excitation energy is a few times smaller than the wall formula predictions. Qualitatively similar results are obtained for the diffused Woods-Saxon well. The details and possible origins of this behaviour are discussed as well as the consequences for the one-body dissipation model of nuclear dynamics.

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arXiv1997

Equilibrium shapes and high-spin properties of the neutron-rich A~100 nuclei

Shapes and high-spin properties of nuclei from the neutron-rich (N>56) zirconium region are calculated using the Nilsson-Strutinsky method with the cranked Woods-Saxon average potential and monopole pairing residual interaction. The shape coexistence effects and the competition between rotationally-aligned 1h11/2 neutron and 1g9/2 proton bands is discussed. Predictions are made for the low-lying superdeformed bands in this mass region, characterized by the intruder states originating from the N=5 and 6 oscillator shells.

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arXiv1995

Antiprotonic studies of nuclear neutron haloes

Nuclear capture of antiprotons from atomic states is studied. Partial widths for single nucleon capture events leading to cold residual nuclei are calculated. Recent CERN experiments that compare the neutron and proton captures are analysed. Nuclear density distributions at extreme nuclear surface are calculated and tested against the experimental results.

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