Nuclear level densities

1982 ◽  
Vol 60 (10) ◽  
pp. 1502-1509 ◽  
Author(s):  
R. U. Haq ◽  
S. S. M. Wong
Keyword(s):  
Experimental Data ◽  
Single Particle ◽  
Steepest Descent ◽  
Interacting Particles ◽  
Nuclear Level ◽  
Body Interaction ◽  
Level Densities ◽  
Statistical Spectroscopy ◽  
Method Of Steepest Descent ◽  
Good Agreement

Nuclear level densities are obtained by first calculating the density for non-interacting particles using the Darwin–Fowler method and then folding in approximately the effects of the residual two-body interaction. For the former, the equations resulting from the method of steepest descent are solved numerically with a realistic set of single particle energies and the latter is then incorporated using statistical spectroscopy considerations. Good agreement with experimental data is found.

Excited quasiparticles and entropy in 161,162Dy

2015 ◽  
Vol 24 (11) ◽  
pp. 1550090 ◽  
Author(s):  
R. Razavi ◽  
A. Rashed Mohassel ◽  
S. Mohammadi
Keyword(s):  
Experimental Data ◽  
Microscopic Theory ◽  
Pairing Interaction ◽  
Nuclear Level ◽  
Level Densities ◽  
Neutron Hole ◽  
Harmonic Oscillator Model ◽  
Nuclear Temperature ◽  
The Difference ◽  
Good Agreement

In this paper, the nuclear level densities of [Formula: see text]Dy is studied by the use of a microscopic theory which includes nuclear pairing interaction. It is based on the modified harmonic oscillator model according to the Nilsson potential. The entropy of even–odd and even–even nuclei as a function of nuclear temperature is obtained. The entropy excess of [Formula: see text]Dy is compared with that of [Formula: see text]Dy. It is concluded that the difference is related to the entropy carried by the neutron hole coupled to the even–even core. The numbers of excited quasiparticles are calculated. Good agreement was observed between calculated results and the experimental data.

scholarly journals Nuclear level densities away from line of β-stability

2021 ◽  
Author(s):  
Tanmoy Ghosh ◽  
Bhoomika Maheshwari ◽  
Sangeeta Arora ◽  
Gaurav Saxena ◽  
Bijay Agrawal
Keyword(s):  
Single Particle ◽  
Level Density ◽  
Mass Range ◽  
Density Parameter ◽  
Structural Effects ◽  
Mass Model ◽  
Nuclear Level ◽  
Level Densities ◽  
Shell Effects ◽  
Order Of Magnitude

Abstract The variation of total nuclear level densities (NLDs) and level density parameters with proton number Z are studied around the β-stable isotope, Z0, for a given mass number. We perform our analysis for a mass range A=40 to 180 using the NLDs from popularly used databases obtained with the single-particle energies from two different microsopic mass-models. These NLDs which include microscopic structural effects such as collective enhancement, pairing and shell corrections, do not exhibit inverted parabolic trend with a strong peak at Z0 as predicted earlier. We also compute the NLDs using the single-particle energies from macroscopic-microscopic mass-model. Once the collective and pairing effects are ignored, the inverted parabolic trends of NLDs and the corresponding level density parameters become somewhat visible. Nevertheless, the factor that governs the (Z-Z0) dependence of the level density parameter, leading to the inverted parabolic trend, is found to be smaller by an order of magnitude. We further find that the (Z-Z0) dependence of NLDs is quite sensitive to the shell effects.

The effect of shell closure on the thermodynamic properties of 207Pb and 89Y

2016 ◽  
Vol 25 (11) ◽  
pp. 1650098 ◽  
Author(s):  
V. Dehghani ◽  
Gh. Forozani ◽  
Kh. Benam
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Excitation Energy ◽  
Low Temperatures ◽  
Shell Closure ◽  
Nuclear Level ◽  
Bcs Model ◽  
Level Densities ◽  
Entropy Contribution

Nuclear level densities of [Formula: see text]Pb and [Formula: see text]Y are calculated using the Lipkin–Nogami (LN) method and Bradeen–Cooper–Schrieffer (BCS) model. It is revealed that the calculated nuclear level densities are highly matched with the experimental data of Oslo group. The excitation energy and entropy are calculated for mentioned nuclei. In the case of two studied nuclei the characteristic of being magic for the number of neutrons or protons causes the decrease of the excitation energy and entropy contribution of magic system at low temperatures.

Back shifted Fermi gas model with temperature dependent pairing energy: Thermal properties of 98Mo

2016 ◽  
Vol 25 (09) ◽  
pp. 1650065
Author(s):  
S. A. Alavi ◽  
V. Dehghani
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Level Density ◽  
Fermi Gas ◽  
Nuclear Level Density ◽  
Temperature Dependent ◽  
Nuclear Level ◽  
Ginzburg Landau ◽  
The Mean ◽  
Good Agreement

The effect of using a temperature dependent pairing term in back-shifted Fermi-gas (BSFG) formula of nuclear level density has been studied. We have used the mean order parameter formula of modified Ginzburg–Landau (MGL) theory as a simple possible choice for temperature dependency of the pairing term. The level density and heat capacity of [Formula: see text]Mo have been calculated with this formalism and compared with the experimental data. We observed good agreement between the heat capacity of this model and the experimental data.

NUCLEAR LEVEL DENSITY AT FINITE TEMPERATURES

2006 ◽  
Vol 15 (02) ◽  
pp. 478-483 ◽  
Author(s):  
J. BARTEL ◽  
K. POMORSKI ◽  
B. NERLO-POMORSKA
Keyword(s):  
Single Particle ◽  
Level Density ◽  
Mean Field ◽  
Skyrme Force ◽  
Nuclear Level Density ◽  
Nuclear Level ◽  
Level Densities ◽  
Relativistic Mean Field ◽  
Single Particle Level ◽  
Particle Level

Selfconsistent mean-field calculations have been performed with the SkM* Skyrme force for 140 spherical even-even nuclei at temperatures 0≤T≤4 MeV . Single-particle level densities for this sample of nuclei are determined for various temperatures. The average dependence of the single-particle level density on mass number A and isospin is given and compared with previous estimates obtained using the relativistic mean-field and different semiclassical approaches.

SINGLE-PARTICLE EXCITATIONS IN SUPERFLUID HELIUM

1991 ◽  
Vol 05 (10) ◽  
pp. 725-732 ◽  
Author(s):  
V.I. YUKALOV
Keyword(s):  
Experimental Data ◽  
Superfluid Helium ◽  
Single Particle ◽  
Stability Boundary ◽  
Experimental Artifact ◽  
Bose Liquid ◽  
Collective Spectrum ◽  
Good Agreement

We show theoretically that the collective spectrum of a Bose liquid contains, besides the well-known phonon-roton branch, single-particle excitations existing below the roton-stability boundary k r , but above a threshold kt. The existence of these single-particle excitations is not an experimental artifact as has been supposed earlier. Calculations made for superfluid helium give the threshold momentum k t ≅1 Å−1. This value and the attenuation found of the single-particle excitations are in very good agreement with experimental data.

scholarly journals Spin-tensor decomposition: A useful tool for shell model effective interaction

2019 ◽  
Vol 223 ◽  
pp. 01029
Author(s):  
Pawan Kumar ◽  
Shahariar Sarkar ◽  
Pushpendra .P Singh ◽  
P. K. Raina
Keyword(s):  
Experimental Data ◽  
Shell Model ◽  
Single Particle ◽  
Effective Interaction ◽  
Tensor Decomposition ◽  
Spin Tensor ◽  
Good Agreement ◽  
Calculated Level

The spin-tensor decomposition is employed to construct a new interaction, named CKHeN, for 0p-shell. This new interaction is used to calculate the ekective single-particle energies of π0p1/2 and π0p1/2orbitals in Li isotopes, and the level structures of 7,8,9Li isotopes. The calculated level structures are found in good agreement with experimental data.

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