arXiv subjects

P. Jachimowicz

Publications and source records attributed to P. Jachimowicz.

21 records · Page 2Linked to original sources

arXiv2013

8Dim calculations of the third barrier in $^{232}$Th and a conflict between theory and experiment on uranium nuclei

We find the height of the third fission barrier $B_{III}$ and energy of the third minimum $E_{III}$ in $^{232}$Th using the macroscopic - microscopic model, very well tested in this region of nuclei. For the first time it is done on an 8-dimensional deformation hypercube. The dipole distortion is included among the shape variables to assure that no important shapes are missed. The saddle point is found on a lattice containing more than 50 million points by the immersion water flow (IWF) method. The shallow third minimum, $B_{III}-E_{III}\approx 0.36$ MeV, agrees with experimetal data of Blons et al. This is in a sharp contrast with the status of the IIIrd minima in $^{232-236}$U: their experimental depth of $\geq3$ MeV contradicts all realistic theoretical predictions. We emphasize the importance of repeating the experiment on $^{232}$Th, by a technique similar to that used in the uranium nuclei, for settling the puzzle of the third minima in actinides.

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arXiv2012

Ground State and Saddle Point: masses and deformations for even-even superheavy nuclei with 98 < Z < 126 and 134< N < 192

We determine ground-state and saddle-point shapes and masses of even-even superheavy nuclei in the range of proton numbers $98\leq Z \leq 126$ and neutron numbers $134\leq N \leq 192$. Our study is performed within the microscopic-macroscopic method. The Strutinsky shell and pairing correction is calculated for the deformed Woods-Saxon single-particle potential and the Yukawa-plus-exponential energy is taken as a smooth part. We use parameters of the model that were fitted previously to this region of nuclei. A high-dimensional deformation space, including nonaxial and reflection-asymmetric shapes, is used in the search for saddle points. Both ground-state and saddle-point shapes are found with the aid of the minimization procedure, with dynamical programming technique of search for saddle points. The results are collected in two tables. Calculated ground-state mass-excess, $Q_{α$ energies, total and macroscopic energies normalized to the macroscopic energy at the spherical shape, shell corrections (including pairing) and deformations are given for each nucleus in the table one. The second table gives the same properties, but at the saddle-point configuration. The obtained results are discussed and compared with available experimental data for alpha-decay energies ($Q_α$) and ground-state masses.

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arXiv2010

Superdeformed Oblate Superheavy Nuclei?

We study stability of superdeformed oblate (SDO) superheavy $Z\geq 120$ nuclei predicted by systematic macroscopic-microscopic calculations in 12D deformation space and confirmed by the Hartree-Fock calculations with the realistic SLy6 force. We include into consideration high-$K$ isomers that very likely form at the SDO shape. Although half-lives $T_{1/2}\lesssim10^{-5}$ s are calclulated or estimated for even-even spin zero systems, decay hindrances known for high-$K$ isomers suggest that some SDO superheavy nuclei may be detectable by the present experimental technique.

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