Semiempirical atomic mass formula

The spin cutoff parameter determining the nuclear level density spin distribution ρ(J) is defined through the spin projection as < J 2 z > 1/2 or equivalently for spherical nuclei, (It is needed to divide the total level density into levels as a function of J. To obtain the total level density at the neutron binding energy from the s-wave resonance count, the spin cutoff parameter is also needed. The spin cutoff parameter has been calculated as a function of excitation energy and mass with a super-conducting hamiltonian. Calculations have been compared with two commonly used semi-empirical formulas. A need for further measurements is also observed. Some complications for deformed nuclei are discussed. The quality of spin cut off parameter data derived from isomeric ratio measurement is examined.

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“…[12][13][14]. Calculations were done for A=20,...,100 in steps of ten and A=100,...., 240 in steps of 20.…”

Section: B Microscopical Modelmentioning

confidence: 99%

Mass-number and excitation-energy dependence of the spin cutoff parameter

2016

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“…Thus, the asymmetry energy provides for an equilibrium between proton and neutron number, vanishes for n n = n p , and lowers the total binding energy B by increasing the difference n n − n p . The empirical value of the asymmetry energy coefficient at the saturation density (3) is also well known [4]:…”

Section: Introductionmentioning

confidence: 99%

Parametrization of the relativisticσ-ωmodel for nuclear matter

Dadi

2010

Phys. Rev. C

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We have investigated the zero-temperature equation of state (EoS) for infinite nuclear matter within the (σ − ω) model at all densities nB and different proton-neutron asymmetry η ≡ (N −Z)/(N +Z). We have presented an analytical expression for the compression modulus, and found that nuclear matter ceases to saturate at η slightly larger than 0.8. Afterward, we have developed an analytical method to determine the strong coupling constants from the EoS for isospin symmetric nuclear matter, which allow us to reproduce all the saturation properties with high accuracy. For various values of the nucleon effective mass and the compression modulus, we have found that the quartic self-coupling constant G4 is negative, or positive and very large. Furthermore, we have demonstrated that it is possible (a) to investigate the EoS in terms of nB and η; and (b) to reproduce all the known saturation properties without G4. We have thus concluded that the latter is not necessary in the (σ − ω) model.

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“…It was also shown that there are large variations in the curvature energy among the results for different interactions. Incidentally, the curvature term of the LDM is poorly known even from empirical nuclear masses [40,41]. The curvature corrections for other pasta phases were also investigated by utilizing the Hartree-Fock theory [42] and the Thomas-Fermi approximation [43].…”

Section: Figmentioning

confidence: 99%

Curvature effect on nuclear “pasta”: Is it helpful for gyroid appearance?

2011

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In supernova cores and neutron star crusts, nuclei are thought to deform to rodlike and slablike shapes, which are often called nuclear pasta. We study the equilibrium properties of the nuclear pasta by using a liquid drop model with curvature corrections. It is confirmed that the curvature effect acts to lower the transition densities between different shapes. We also examine the gyroid structure, which was recently suggested as a different type of nuclear pasta by analogy with the polymer systems. The gyroid structure investigated in this paper is approximately formulated as an extension of the periodic minimal surface whose mean curvature vanishes. In contrast to our expectations, we find from the present approximate formulation that the curvature corrections act to slightly disfavor the appearance of the gyroid structure. By comparing the energy corrections in the gyroid phase and the hypothetical phases composed of d-dimensional spheres, where d is a general dimensionality, we show that the gyroid is unlikely to belong to a family of the generalized dimensional spheres.

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Semiempirical atomic mass formula

Cited by 179 publications

References 19 publications

Mass-number and excitation-energy dependence of the spin cutoff parameter

Mass-number and excitation-energy dependence of the spin cutoff parameter

Parametrization of the relativisticσ-ωmodel for nuclear matter

Curvature effect on nuclear “pasta”: Is it helpful for gyroid appearance?

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