scholarly journals Deformed Hartree-Fock calculations for semileptonic processes in nuclei

2019 ◽  
Vol 11 ◽  
Author(s):  
T. S. Kosmas
Keyword(s):  
Single Particle ◽  
Good Description ◽  
Effective Interaction ◽  
Random Phase ◽  
Model Space ◽  
Spectroscopic Properties ◽  
Particle Spectrum ◽  
Hartree Fock ◽  
Nuclear Systems ◽  
Nuclear Processes

In nuclear structure calculations, the Deformed Hartree-Fock (DHF) provides generally a good description for the low-lying spectroscopic properties of odd-even, odd-odd and even-even nuclear systems of which the consideration of the deformation is motivated by many reasons. The common random phase approximations (RPA, QRPA, etc.) mostly used to accurately evaluate the transition matrix elements in many nuclear processes [1,2], are appropriate for only spherical even-even nuclear systems even though, sometimes, isotopes considered as rather deformed are studied. In the present work, we discuss the treatment within the DHF method of nuclei in the region A = 70 — 80. This region includes isotopes (like 72Ge, 76Ge, 72Se, etc) interesting for studying many nuclear processes as the ,0/3-decay, scattering of dark matter candidates off nuclei, μ~ —> e± conversions in nuclei. In our calculations the model space comprises 1P3/2, 0f5/2, 1pi/2 and 0p9/2 single particle Orbitals assuming 56Ni to be the inert core. The effective interaction employed, has been quite successfully used previously to describe many important features of the nuclei in this region. The lowest prolate Hartree-Fock single particle spectrum of some isotopes (72Ge, 76Ge) has been used to test the good angular momentum states which in this method are projected out from the intrinsic HF states. As an application, we examine the predictions of DHF for the exotic (μ~,ε~) conversion process. The contributions of all basic μ~ —> e~ operators originating from a general effective Lagrangian [2] are compared with those of normal QRPA methods obtained previously.

scholarly journals Deformed shell model results for neutrinoless double beta decay of nuclei in A = 60 - 90 region

2015 ◽  
Vol 24 (03) ◽  
pp. 1550022 ◽  
Author(s):  
R. Sahu ◽  
V. K. B. Kota
Keyword(s):  
Shell Model ◽  
Beta Decay ◽  
Good Description ◽  
Effective Interaction ◽  
Model Space ◽  
Spectroscopic Properties ◽  
Neutrinoless Double Beta Decay ◽  
Double Beta Decay ◽  
Hartree Fock ◽  
Transition Matrix Elements

Nuclear transition matrix elements (NTME) for the neutrinoless double beta decay (Oνββ or OνDBD) of 70 Zn , 80 Se and 82 Se nuclei are calculated within the framework of the deformed shell model (DSM) based on Hartree–Fock (HF) states. For 70 Zn , jj44b interaction in 2p3/2, 1f5/2, 2p1/2 and 1g9/2 space with 56 Ni as the core is employed. However, for 80 Se and 82 Se nuclei, a modified Kuo interaction with the above core and model space are employed. Most of our calculations in this region were performed with this effective interaction. However, jj44b interaction has been found to be better for 70 Zn . The above model space was used in many recent shell model (SM) and interacting boson model (IBM) calculations for nuclei in this region. After ensuring that DSM gives good description of the spectroscopic properties of low-lying levels in these three nuclei considered, the NTME are calculated. The deduced half-lives with these NTME, assuming neutrino mass is 1 eV, are 1.1 × 1026, 2.3 × 1027 and 2.2 × 1024 yr for 70 Zn , 80 Se and 82 Se , respectively.

scholarly journals Shell model and Hartree-Fock calculations of electron scattering form factors for 25Mg nucleus

2019 ◽  
Vol 14 (31) ◽  
pp. 28-36
Author(s):  
Ali A. Alzubadi
Keyword(s):  
Shell Model ◽  
Electron Scattering ◽  
Single Particle ◽  
Effective Interaction ◽  
Form Factors ◽  
Model Space ◽  
Inelastic Electron ◽  
Hartree Fock ◽  
Particle Potential ◽  
Single Particle Potential

Shell model and Hartree-Fock calculations have been adopted to study the elastic and inelastic electron scattering form factors for 25Mg nucleus. The wave functions for this nucleus have been utilized from the shell model using USDA two-body effective interaction for this nucleus with the sd shell model space. On the other hand, the SkXcsb Skyrme parameterization has been used within the Hartree-Fock method to get the single-particle potential which is used to calculate the single-particle matrix elements. The calculated form factors have been compared with available experimental data.

STUDY OF SINGLE-PARTICLE RESONANT STATES

2004 ◽  
Vol 19 (20) ◽  
pp. 1537-1545 ◽  
Author(s):  
SHISHENG ZHANG
Keyword(s):  
Single Particle ◽  
Effective Interaction ◽  
Random Phase ◽  
Mean Field ◽  
Coupling Constant ◽  
Relativistic Mean Field ◽  
Resonant States ◽  
Scattering Phase ◽  
First Time ◽  
Phase Shift Method

Energies and widths for single-particle resonant states in the continuum in 120 Sn , as the necessary input quantities of relativistic random phase approximation for the investigation of isoscalar giant octupole resonance, are determined by analytic continuation in the coupling constant (ACCC) method within the framework of self-consistent relativistic mean field (RMF) theory for the first time. For the effective interaction NL3, the results in this scheme agree well with those of scattering phase shift method on the basis of RMF. Similar calculations are carried out in neutron-rich nucleus 84 Ni .

Deformed shell model results for two-neutrino double-beta decay of 82Se

2011 ◽  
Vol 89 (11) ◽  
pp. 1101-1105 ◽  
Author(s):  
R. Sahu ◽  
P.C. Srivastava ◽  
V.K.B. Kota
Keyword(s):  
Shell Model ◽  
Beta Decay ◽  
Half Life ◽  
Model Space ◽  
Spectroscopic Properties ◽  
Double Beta Decay ◽  
Hartree Fock ◽  
The Past ◽  
Quenching Factor ◽  
Reasonable Description

The half-life for two-neutrino double-beta decay has been calculated for 82Se, within the framework of the deformed shell model (DSM) based on Hartree–Fock states employing a modified Kuo interaction in 2p3/2, 1f5/2, 2p1/2, and 1g9/2 space with single particle energies (relative to a 56Ni core) for the four orbitals taken as 0.0, 0.78, 1.08, and 4.25 MeV, respectively. A reasonable description is obtained for the spectroscopic properties of yrast levels in 82Se, and similarly in the past 82Kr was studied successfully using DSM. The half-life calculated using DSM is ∼3.56 × 1020 a compared to the experimental value (0.92 ± 0.07) × 1020 a. We have also recalculated the half-life by including the 1f7/2 orbit in the preceding model space using the fpg interaction introduced by Sorlin et al. (Phys. Rev. Lett. 88, 092501 (2002)). The calculated half-life is 2.05 × 1019 a (0.58 × 1020 a if we include the quenching factor of 0.77).

scholarly journals Inelastic Form Factor Calculations for 46,48,50Ti Isotopes Using Tassie Model

2021 ◽  
Vol 2021 ◽  
pp. 1-4
Author(s):  
Mohanad H. Oleiwi
Keyword(s):  
Experimental Data ◽  
Wave Function ◽  
Momentum Transfer ◽  
Good Description ◽  
Effective Interaction ◽  
Form Factors ◽  
Model Space ◽  
Single Particle Wave Function ◽  
Particle Wave Function ◽  
Theoretical Results

Inelastic form factors of electrical transition have been calculated for 46,48,50Ti isotopes using the Tassie model. The form factors have been calculated for different exciting energies. The harmonic oscillator (HO) wave function has been used as a single-particle wave function. The model space has been considered as 1f7/2, 2p3/2, 2p1/2, and 2f5/2. Gx1 has been used as effective interaction in all calculations. In all calculations, the effective charge has been considered as 1.5e for proton and 0.5e for neutron. All obtained results have been compared with data from an experiment. The calculations show the Tassie model gives a good description of longitudinal form factors of 46,48,50Ti isotopes in E(2+) transitions as compared with experimental data, especially in the region below 2 fm−1 of momentum transfer, but in the E(4+), the theoretical results deviated slightly from experimental data especially in the region greater than 1.5 fm−1 of momentum transfer.

scholarly journals Evolution of nuclear spin-orbit splittings with Skyrme functional SAMi-T

2019 ◽  
Vol 223 ◽  
pp. 01059
Author(s):  
Shihang Shen ◽  
Gianluca Colò ◽  
Xavier Roca-Maza
Keyword(s):  
Single Particle ◽  
Good Description ◽  
Mean Field ◽  
Tensor Force ◽  
Particle Energy ◽  
Single Particle Energy ◽  
Giant Resonances ◽  
Hartree Fock ◽  
Nuclear Ground State ◽  
Vibration Coupling

A new Skyrme functional has been developed with tensor term guided by ab initio relativistic Brueckner-Hartree-Fock (RBHF) studies on neutron-proton drops. Instead of extracting information on the tensor force from experimental single-particle energy splittings, the RBHF calculations do not contain beyond mean-field effects such as particle-vibration coupling and therefore the information on the tensor force can be obtained without ambiguities. The new functional gives a good description of nuclear ground-state properties aswell as various giant resonances. The description for the evolution of single-particle energy splittings is also improved by the new functional.

scholarly journals Unraveling the electrochemical and spectroscopic properties of neutral and negatively charged perylene tetraethylesters

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christian Wiebeler ◽  
Joachim Vollbrecht ◽  
Adam Neuba ◽  
Heinz-Siegfried Kitzerow ◽  
Stefan Schumacher
Keyword(s):  
Absorption Spectra ◽  
Density Functional ◽  
Energy Levels ◽  
Spectroscopic Properties ◽  
Absorption Bands ◽  
Functional Theory ◽  
Vertical Excitation ◽  
Hartree Fock ◽  
Tauc Plot ◽  
Electrochemical Approach

AbstractA detailed investigation of the energy levels of perylene-3,4,9,10-tetracarboxylic tetraethylester as a representative compound for the whole family of perylene esters was performed. It was revealed via electrochemical measurements that one oxidation and two reductions take place. The bandgaps determined via the electrochemical approach are in good agreement with the optical bandgap obtained from the absorption spectra via a Tauc plot. In addition, absorption spectra in dependence of the electrochemical potential were the basis for extensive quantum-chemical calculations of the neutral, monoanionic, and dianionic molecules. For this purpose, calculations based on density functional theory were compared with post-Hartree–Fock methods and the CAM-B3LYP functional proved to be the most reliable choice for the calculation of absorption spectra. Furthermore, spectral features found experimentally could be reproduced with vibronic calculations and allowed to understand their origins. In particular, the two lowest energy absorption bands of the anion are not caused by absorption of two distinct electronic states, which might have been expected from vertical excitation calculations, but both states exhibit a strong vibronic progression resulting in contributions to both bands.

AN INVESTIGATION ON SHAPE EVOLUTION OF Ti ISOTOPES WITH HARTREE–FOCK–BOGOLIUBOV THEORY

2012 ◽  
Vol 27 (28) ◽  
pp. 1250162 ◽  
Author(s):  
TUNCAY BAYRAM
Keyword(s):  
Potential Energy ◽  
Single Particle ◽  
Potential Energy Curves ◽  
Shape Evolution ◽  
Shape Transition ◽  
Hartree Fock ◽  
Bogoliubov Theory ◽  
Unstable Nuclei

Constrained Hartree–Fock–Bogoliubov theory with SLy4 and SLy5 Skyrme forces is used to investigate the shape transition between spherical and γ-unstable nuclei in 38–66 Ti . By examining potential energy curves and neutron single-particle levels of even–even Ti isotopes, 46,52,60 Ti are suggested as possible candidates of the nuclei with E(5) symmetry.

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