Hartree-Fock-Bogoliubov Fission Barriers with Skyrme Forces Adjusted on Masses

Author(s):  
M. Samyn
2008 ◽  
Vol 17 (01) ◽  
pp. 151-159 ◽  
Author(s):  
J. SKALSKI

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 SLy 6 show that the correction, previously estimated as ~ 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.


2011 ◽  
Vol 20 (02) ◽  
pp. 557-564 ◽  
Author(s):  
A. BARAN ◽  
A. STASZCZAK ◽  
W. NAZAREWICZ

Nuclear fission barriers, mass parameters and spontaneous fission half lives of fermium isotopes calculated in a framework of the Skyrme Hartree-Fock-Bogoliubov model with the SkM* force are discussed. Zero-point energy corrections in the ground state are determined for each nucleus using the Gaussian overlap approximation of the generator coordinate method and in the cranking formalism. Results of spontaneous fission half lives are compared to experimental data.


2006 ◽  
Vol 15 (02) ◽  
pp. 302-310 ◽  
Author(s):  
ANDRZEJ STASZCZAK ◽  
JACEK DOBACZEWSKI ◽  
WITOLD NAZAREWICZ

Constrained Skyrme-Hartree-Fock calculations of static fission barriers are performed for even-even elements with Z = 100÷110 as well as for superheavy N=184 isotones. In our study we use the Skyrme parametrization SLy4 and a seniority pairing force treated in the BCS approximation. The computations are carried out applying a code that makes it possible to break all self-consistent symmetries of the nuclear mean field, including axial symmetry and reflection symmetry. The influence of reflection-asymmetric and triaxial degrees of freedom on fission barriers are discussed.


2005 ◽  
Vol 14 (03) ◽  
pp. 395-402 ◽  
Author(s):  
ANDRZEJ STASZCZAK ◽  
JACEK DOBACZEWSKI ◽  
WITOLD NAZAREWICZ

Self-consistent Skyrme–Hartree–Fock (SHF) calculations of static fission barriers are presented for even-even Fermium isotopes as well as for superheavy even-even N=184 isotones. In the particle-hole channel, we use the SLy4 Skyrme parametrization, while in the particle-particle channel we take a T=1 seniority pairing force treated in the BCS approximation. The influence of reflection-asymmetric and triaxial degrees of freedom on the static fission paths are investigated.


2007 ◽  
Vol 16 (02) ◽  
pp. 443-451 ◽  
Author(s):  
A. BARAN ◽  
A. STASZCZAK ◽  
J. DOBACZEWSKI ◽  
W. NAZAREWICZ

Spontaneous fission barriers, quadrupole inertia tensor, and zero-point quadrupole correlation energy are calculated for 252,256,258 Fm in the framework of the self-consistent Skyrme-Hartree-Fock+BCS theory. Two ways of computing collective inertia are employed: the Gaussian Overlap Approximation to the Generator Coordinate Method and cranking ansatz. The Skyrme results are compared with those of the Gogny-Hartree-Fock-Bogolyubov model.


2007 ◽  
Author(s):  
K. Hashizume ◽  
T. Wada ◽  
M. Ohta ◽  
M. Samyn ◽  
S. Goriely

Author(s):  
J. Taft∅

It is well known that for reflections corresponding to large interplanar spacings (i.e., sin θ/λ small), the electron scattering amplitude, f, is sensitive to the ionicity and to the charge distribution around the atoms. We have used this in order to obtain information about the charge distribution in FeTi, which is a candidate for storage of hydrogen. Our goal is to study the changes in electron distribution in the presence of hydrogen, and also the ionicity of hydrogen in metals, but so far our study has been limited to pure FeTi. FeTi has the CsCl structure and thus Fe and Ti scatter with a phase difference of π into the 100-ref lections. Because Fe (Z = 26) is higher in the periodic system than Ti (Z = 22), an immediate “guess” would be that Fe has a larger scattering amplitude than Ti. However, relativistic Hartree-Fock calculations show that the opposite is the case for the 100-reflection. An explanation for this may be sought in the stronger localization of the d-electrons of the first row transition elements when moving to the right in the periodic table. The tabulated difference between fTi (100) and ffe (100) is small, however, and based on the values of the scattering amplitude for isolated atoms, the kinematical intensity of the 100-reflection is only 5.10-4 of the intensity of the 200-reflection.


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