Di-neutron Cluster and Its Condensation

2006 ◽  
Vol 21 (31n33) ◽  
pp. 2455-2459 ◽  
Author(s):  
Hisashi Horiuchi
Keyword(s):  
Wave Function ◽  
Cluster Structure ◽  
Surface Region ◽  
Hybrid Wave ◽  
Neutron Cluster

Di-neutron cluster structure of 11 Li which is suggested strongly by recent experiments is discussed. Recent HFB calculations which show clear di-neutron correlation in surface region of neutron-rich nuclei are also discussed. An approach to di-neutron problem by the use of a hybrid wave function of AMD and di-neutron condensed wave function is proposed.

DESCRIPTION OF 8Be AS DEFORMED GAS-LIKE TWO-ALPHA-PARTICLE STATES

2003 ◽  
Vol 18 (02n06) ◽  
pp. 170-173
Author(s):  
Y. FUNAKI ◽  
H. HORIUCHI ◽  
A. TOHSAKI ◽  
P. SCHUCK ◽  
G. RÖPKE
Keyword(s):  
Wave Function ◽  
Excited States ◽  
Ground State ◽  
Cluster Structure ◽  
Test Case ◽  
Weakly Bound ◽  
Generator Coordinate Method ◽  
Spatial Deformation ◽  
Generator Coordinate ◽  
Spin Excitations

In order to study non-zero spin excitations of the recently proposed α-cluster condensation in the self-conjugate 4n nuclei, spatial deformation is introduced into the model wave function of the α-cluster condensate. The rotational band states of 8 Be are investigated as a first step of a test case for the study of the deformation of the α-cluster condensate. Calculations reproduce well the binding energy of the 0+ ground state and also the excitation energy of the 2+ state. Our 0+ wave function is found to be exactly equal to the 0+ wave function obtained by the generator coordinate method using Brink's 2α wave function. The study shows that both the 0+ ground and 2+ excited states can be considered as having a gas-like (i.e. weakly bound) 2α-cluster structure.

DI-NEUTRON CORRELATIONS IN THE SUPER NEUTRON-RICH NUCLEUS; 7H

2010 ◽  
Vol 25 (21n23) ◽  
pp. 1828-1832
Author(s):  
S. AOYAMA ◽  
N. ITAGAKI
Keyword(s):  
Wave Function ◽  
Binding Properties ◽  
Type Wave ◽  
Neutron Rich Nucleus ◽  
Weak Binding ◽  
Neutron Cluster

We study the di-neutron correlations in the super neutron-rich nucleus 7 H with the AMD triple-S (AMD superposition of selected snapshots). 7 H is the most neutron-rich nucleus in the neutron ratio to the proton ( N / Z = 6). And the strong di-neutron correlations are expected due to the weak binding properties. In this paper, the mixing of di-neutron cluster components is estimated by calculating the squared overlap with the di-neutron condensate type wave function. The calculated results show significant mixing of di-neutron (t + 2n + 2n) components (70 ~ 80%).

scholarly journals Existence of core excited 8Be* = α+α* cluster structure in α+α scattering

2021 ◽  
Author(s):  
Yoshiharu Hirabayashi ◽  
Shigeo Ohkubo
Keyword(s):  
Wave Function ◽  
Excited State ◽  
Cluster Structure ◽  
Experimental Phase ◽  
Folding Model ◽  
Double Folding Model ◽  
Coupled Channels ◽  
First Excited State ◽  
Double Folding ◽  
First Time

Abstract We show the existence of the α+α * cluster structure at the highly excited energy around Ex =20 MeV in 8Be for the first time in the coupled channels calculations. An extended double folding model derived using a realistic precise cluster wave function with a well-developed N+3N cluster structure for the first excited state of 4He was employed. The calculation reproduces the experimental phase shifts in α+α scattering up to Ec.m. =21 MeV well. The result shows that the well-developed core-excited α+α * structure appears as resonances for L=0 and 2 near the α+α * threshold which correspond to the experimental states at Ex =20.20MeV and Ex =22.24MeV in 8Be.

Calculation of the Electric Quadrupole Moment of 6Li and 7Li in Shell Model and Cluster Model

2021 ◽  
Vol 14 (4) ◽  
pp. 333-338
Keyword(s):  
Wave Function ◽  
Shell Model ◽  
Quadrupole Moment ◽  
Cluster Model ◽  
Particle System ◽  
Cluster Structure ◽  
Electric Quadrupole ◽  
Experimental Results ◽  
Electric Quadrupole Moment ◽  
Model Calculations

Abstract: In this paper, we have investigated electric quadrupole moment of (_^6)Li and (_^7)Li in both shell model and cluster model. In shell model, the nuclei (_^6)Li and (_^7)Li can be modeled as one core plus nucleons. Nucleons outside the closed shell can be considered as a two- and three-particle system. In cluster structure, we have selected alpha clusters and triton or deuteron in interaction with alpha cluster ((_^7)Li and (_^6)Li involving α+(_^3)H and α+(_^2)H, respectively). By solving Schrödinger equation and using suitable potential for interaction between particles by applying Nikiforov-Uvarov method, potential coefficients have been computed. Then, we have calculated the energy and wave function for nuclei(_^6)Li and (_^7)Li and compared the results obtained with experimental results. By having the wave function, we can obtain the quadrupole moment. These values are compared with predictions from shell-model and cluster-model calculations. Although the difference between them is small, the electric quadrupole moment results in the cluster model are in good agreement with experimental results. Keywords: Electric quadrupole moment, Shell-model, Cluster-model, Li isotopes, Non-relativistic equation.

Analytic integration of contrast transfer functions

1988 ◽  
Vol 46 ◽  
pp. 822-823
Author(s):  
Peter Rez
Keyword(s):  
Wave Function ◽  
Transfer Function ◽  
Transfer Functions ◽  
Spherical Aberration ◽  
Continuous Distribution ◽  
Objective Lens ◽  
Direction Parallel ◽  
Scattering Angle ◽  
Analytic Integration ◽  
Image Position

In high resolution microscopy the image amplitude is given by the convolution of the specimen exit surface wave function and the microscope objective lens transfer function. This is usually done by multiplying the wave function and the transfer function in reciprocal space and integrating over the effective aperture. For very thin specimens the scattering can be represented by a weak phase object and the amplitude observed in the image plane is1where fe (Θ) is the electron scattering factor, r is a postition variable, Θ a scattering angle and x(Θ) the lens transfer function. x(Θ) is given by2where Cs is the objective lens spherical aberration coefficient, the wavelength, and f the defocus.We shall consider one dimensional scattering that might arise from a cross sectional specimen containing disordered planes of a heavy element stacked in a regular sequence among planes of lighter elements. In a direction parallel to the disordered planes there will be a continuous distribution of scattering angle.

A technique to prepare cross-sectional TEM specimens of semiconducting devices

1986 ◽  
Vol 44 ◽  
pp. 742-743
Author(s):  
A. K. Rai ◽  
P. P. Pronko
Keyword(s):  
Thin Films ◽  
Surface Region ◽  
Sample Surface ◽  
Specific Region ◽  
Cross Sectional ◽  
Thin Sections ◽  
The Past ◽  
Device Structures ◽  
Ion Implanted

Several techniques have been reported in the past to prepare cross(x)-sectional TEM specimen. These methods are applicable when the sample surface is uniform. Examples of samples having uniform surfaces are ion implanted samples, thin films deposited on substrates and epilayers grown on substrates. Once device structures are fabricated on the surfaces of appropriate materials these surfaces will no longer remain uniform. For samples with uniform surfaces it does not matter which part of the surface region remains in the thin sections of the x-sectional TEM specimen since it is similar everywhere. However, in order to study a specific region of a device employing x-sectional TEM, one has to make sure that the desired region is thinned. In the present work a simple way to obtain thin sections of desired device region is described.

Preparation of cross-sectional samples for near-surface TEM studies

1987 ◽  
Vol 45 ◽  
pp. 380-381
Author(s):  
R.C. Dickenson ◽  
K.R. Lawless
Keyword(s):  
Standard Sample ◽  
Surface Region ◽  
Specimen Preparation ◽  
Thick Sheet ◽  
Drill Bit ◽  
Sample Holder ◽  
Metal Interface ◽  
Cross Sectional ◽  
Near Surface ◽  
Cold Worked

In thermal oxidation studies, the structure of the oxide-metal interface and the near-surface region is of great importance. A technique has been developed for constructing cross-sectional samples of oxidized aluminum alloys, which reveal these regions. The specimen preparation procedure is as follows: An ultra-sonic drill is used to cut a 3mm diameter disc from a 1.0mm thick sheet of the material. The disc is mounted on a brass block with low-melting wax, and a 1.0mm hole is drilled in the disc using a #60 drill bit. The drill is positioned so that the edge of the hole is tangent to the center of the disc (Fig. 1) . The disc is removed from the mount and cleaned with acetone to remove any traces of wax. To remove the cold-worked layer from the surface of the hole, the disc is placed in a standard sample holder for a Tenupol electropolisher so that the hole is in the center of the area to be polished.

Studies of the scanning ion beam sputter-cleaned MgO crystal surface by scanning reflection electron microscopy

1987 ◽  
Vol 45 ◽  
pp. 144-145
Author(s):  
H.-J. Ou ◽  
J. M. Cowley ◽  
A. A. Higgs
Keyword(s):  
Crystal Surface ◽  
Ion Beam ◽  
Carbon Film ◽  
Surface Region ◽  
Bulk Sample ◽  
Chamber Pressure ◽  
Specimen Preparation ◽  
Detailed Surface ◽  
Gate Control ◽  
Reflection Electron Microscopy

A scanning ion gun system has been installed on the specimen preparation chamber (pressure ∼5xl0-8 torr) of the VG-HB5 STEM microscope. By using the specimen current imaging technique, it is possible to use an ion beam to sputter-clean the preferred surface region on a bulk sample. As shown in figure 1, the X-Y raster-gate control of the scanning unit for the Krato Mini-Beam I is used to minimize the beam raster area down to a 800μm x800μm square region. With beam energy of 2.5KeV, the MgO cleavage surface has been ion sputter-cleaned for less than 1 minute. The carbon film or other contaminant, introduced during the cleavage process in air, is mostly removed from the MgO crystal surfaces.The immediate SREM inspection of this as-cleaned MgO surface, within the adjacent STEM microscope, has revealed the detailed surface structures of atomic steps, which were difficult to observe on the as-cleaved MgO surfaces in the previous studies.

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