scholarly journals Signature-dependent triaxiality for shape evolution from superdeformation in rapidly rotating 40Ca and 41Ca

2020 ◽  
Vol 2020 (6) ◽  
Author(s):  
Shinkuro Sakai ◽  
Kenichi Yoshida ◽  
Masayuki Matsuo
Keyword(s):  
Density Functional ◽  
Density Functional Method ◽  
Three Dimensional ◽  
Decisive Role ◽  
Functional Method ◽  
Space Representation ◽  
Coordinate Space ◽  
Shape Evolution ◽  
Energy Density Functional ◽  
Collective Rotation

Abstract We investigate the possible occurrence of highly elongated shapes near the yrast line in $^{40}$Ca and $^{41}$Ca at high spins on the basis of the nuclear energy-density functional method. Both the superdeformed (SD) yrast configuration and the yrare configurations on top of the SD band are described by solving the cranked Skyme–Kohn–Sham equation in the three-dimensional coordinate space representation. It is suggested that some of the excited SD bands undergo band crossings and develop to hyperdeformation (HD) beyond $J \simeq 25 \hbar$ in $^{40}$Ca. We find that the change of triaxiality in response to rotation plays a decisive role in the shape evolution towards HD, and that this is governed by the signature quantum number of the last occupied orbital at low spins. This mechanism can be verified in an experimental observation of the positive-parity SD yrast signature-partner bands in $^{41}$Ca, one of which ($\alpha=+1/2$) undergoes crossings with the HD band, while the other ($\alpha=-1/2$) shows smooth evolution from collective rotation at low spins to non-collective rotation with an oblate shape at termination.

CONSTRAINING SYMMETRY RESTORATION WITHIN THE NUCLEAR ENERGY DENSITY FUNCTIONAL METHOD

2010 ◽  
Vol 25 (21n23) ◽  
pp. 2016-2017
Author(s):  
J. SADOUDI ◽  
T. DUGUET
Keyword(s):  
Wave Function ◽  
Energy Density ◽  
Density Functional ◽  
Nuclear Energy ◽  
Density Functional Method ◽  
Energy Functional ◽  
Functional Method ◽  
Energy Density Functional ◽  
Density Functional Methods ◽  
Functional Methods

We review the notion of symmetry breaking and restoration within the frame of nuclear energy density functional methods. We focus on key differences between wave-function- and energy-functional-based methods. In particular, we point to difficulties to formulate the restoration of symmetries within the energy functional framework.

THE DESCRIPTION AND ROLE OF FLUCTUATIONS IN COLLECTIVE DEGREES OF FREEDOM IN MODELS OF NUCLEAR STRUCTURE BASED ON THE SELF-CONSISTENT MEAN FIELD

2010 ◽  
Vol 25 (21n23) ◽  
pp. 1787-1791
Author(s):  
MICHAEL BENDER ◽  
PAUL-HENRI HEENEN
Keyword(s):  
Nuclear Structure ◽  
Density Functional ◽  
Degrees Of Freedom ◽  
Density Functional Method ◽  
Mean Field ◽  
Functional Method ◽  
Energy Density Functional ◽  
Open Questions ◽  
Self Consistent

This contribution sketches recent efforts to explicitly include fluctuations in collective degrees of freedom into a universal energy density functional method for nuclear structure, their successes, and some remaining open questions.

Fusion barrier parameters for a spherically deformed pair of nuclei

2014 ◽  
Vol 92 (11) ◽  
pp. 1411-1418 ◽  
Author(s):  
M. Ismail ◽  
A.Y. Ellithi ◽  
M.M. Botros ◽  
A.F. Abdel Reheem
Keyword(s):  
Density Functional ◽  
Density Functional Method ◽  
Analytical Formula ◽  
Functional Method ◽  
Effective Density ◽  
Folding Model ◽  
Energy Density Functional ◽  
Deformation Parameters ◽  
Double Folding ◽  
Simple Analytical Formula

The interactions of 48Ca spherical nucleus are considered with the deformed targets 224Ra and 244Pu to form the super heavy elements 272Hs and 292114 (292Fl), respectively. The double folding model with effective density dependent M3Y-NN force, and the energy density functional method based on Skyrme force are used to derive the nucleus–nucleus interaction. The effect of deformation and orientation on the Coulomb barrier parameters is studied, and the results are compared with the corresponding quantities derived from a simple model based on the proximity approach for the nuclear part and simple analytical formula for the Coulomb interaction. Consistent behavior of the results is obtained at certain ranges for deformation parameters and orientations.

scholarly journals Ab initio-driven nuclear energy density functional method

2015 ◽  
Vol 51 (12) ◽  
Author(s):  
T. Duguet ◽  
M. Bender ◽  
J. -P. Ebran ◽  
T. Lesinski ◽  
V. Somà
Keyword(s):  
Energy Density ◽  
Ab Initio ◽  
Density Functional ◽  
Nuclear Energy ◽  
Density Functional Method ◽  
Functional Method ◽  
Energy Density Functional

scholarly journals Электронные состояния наноструктурированных систем: титан и диоксид циркония

2018 ◽  
Vol 60 (10) ◽  
pp. 1861
Author(s):  
В.Г. Заводинский
Keyword(s):  
Density Of States ◽  
Density Functional ◽  
Energy Gap ◽  
Density Functional Method ◽  
Three Dimensional ◽  
Electronic States ◽  
Functional Method ◽  
Density Of Electronic States ◽  
Nanostructured Systems ◽  
Ionic Bonds

AbstractThe density functional method with pseudopotentials are used to study the electron states of nanoparticles and nanostructured systems: chains, films, and three-dimensional nanosystems of titanium and zirconia. It is shown that all studied titanium nanosystems have the density of electronic states (DES) of the metallic type, but zirconia nanosystem demonstrates a dielectric energy gap in the vicinity of the Fermi level. The density of states of nanostructured titanium is close in shape to DES of the single crystal but has a smoother shape due to disordering of the atomic arrangement. The forbidden band width of the nanostructured zirconia is smaller as compared to the corresponding width in crystalline ZrO_2, supposedly because of incomplete saturation of ionic bonds.

Description of Substitutional Adsorption of Magnetic Ions on Metallic Surfaces with Formation of Monolayer Ferromagnetic Films Using the Spin-Density Functional Method

2012 ◽  
Vol 190 ◽  
pp. 27-30 ◽  
Author(s):  
S.P. Klimov ◽  
M.V. Mamonova ◽  
Vladimir V. Prudnikov
Keyword(s):  
Spin Density ◽  
Density Functional ◽  
Density Functional Method ◽  
Three Dimensional ◽  
Magnetic Ordering ◽  
Transition Metal Ions ◽  
Functional Method ◽  
Magnetic Characteristics ◽  
Metallic Surfaces ◽  
Ferromagnetic Ordering

At present time, a large number of experimental works have been devoted to the study of magnetic ordering in Fe, Co, and Ni ultrathin films [. The investigation of a nature of magnetism in these structures has a large fundamental interest through an observable dimensionality crossover of magnetic characteristics from three dimensional values for films with thickness d 10 nm to two dimensional values for films with thickness d 1-2 nm. It has been established that the long-range ferromagnetic order arises in films at some effective film thickness. However, the nature and regularities of this phenomenon remain not quite clear. In our paper [ it was developed in terms of the spin-density functional theory the description of influence of the temperature and ferromagnetic ordering on the adsorption of Fe, Co, and Ni transition metal ions on a nonmagnetic substrate with the formation of a submonolayer films. For case of nonactivated adsorption the conditions for the formation of magnetic monoatomic films stable with respect to island adsorption with a change in the coverage parameter θ are revealed. It was demonstrated that the inclusion of the ferromagnetic ordering substantially affects the adsorption energy and leads to its considerable increase.

scholarly journals Влияние флуктуаций на образование выделений вторых фаз на границах зерен

2019 ◽  
Vol 61 (2) ◽  
pp. 357
Author(s):  
П.Е. Львов ◽  
В.В. Светухин
Keyword(s):  
Grain Boundaries ◽  
Density Functional ◽  
Density Functional Method ◽  
Free Energy Density ◽  
Functional Method ◽  
Precipitate Size ◽  
Secondary Phases ◽  
Energy Density Functional ◽  
Initial Stage ◽  
Composition Fluctuations

AbstractBased on the free energy density functional method (modified Cahn–Hillard–Cook equation), the formation kinetics of secondary phases in binary alloys is considered in the presence of composition fluctuations and with inclusion of the grain boundaries influences. It is revealed that the existence of grain boundaries and the fluctuations at the initial stage of the phase transition can lead to the appearance of anomalous growth rate of the average precipitate size due to a competition of various decomposition mechanisms.

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