arXiv subjects

G. K. Nie

Publications and source records attributed to G. K. Nie.

7 recordsLinked to original sources

arXiv2018

Alpha-Cluster Model, Charge Symmetry of Nuclear Force and Single Particle Bound State Potential in Symmetrical Nuclei

A phenomenological alpha-cluster model based on np-pair interactions and the charge symmetry of nuclear force allows one to estimate the Coulomb energy, the Coulomb radius R_C, the Coulomb energy of the last proton interaction with the residual nucleus and the radius of its position R_p in a symmetrical nucleus. The values R_C and R_p obtained for the symmetrical nuclei with 5<= Z<=45 are used in a long standing task of determination of the parameters of the Woods-Saxon potential of neuton/proton bound state used in DWBA analysis of direct one nucleon transfer reactions. According to the charge symmetry of nuclear force a requirement of equality of the nuclear potentials of the last neutron and the last proton in a symmetrical nucleus is added to the standard well-depth procedure in solving the Shrödinger equation, which makes R_C the crucial parameter to determine the parameters of the nuclear potential and the value of the last proton rms radius ^{1/2} in the wave representation. Comparative analysis of the radii ^{1/2} and R_p, R_C, the experimental radii and the nuclear potential radii obtained at the calculations shows that for the nuclei with Z>16 it is inappropriate to represent a single particle bound state by the Woods-Saxon potential. Using asymptotic coefficient of wave function allows one to estimate error in obtaining spectroscopic factor caused by using the standard parameters in DWBA analysis of pure peripheral reactions. It is shown that using these may bring an error up to 48%.

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arXiv2009

Masses and Radii of the Nuclei with N>=Z in an Alpha-Cluster Model

In the framework of a recently developed alpha-cluster model a nucleus is represented as a core (alpha-cluster liquid drop with dissolved excess neutron pairs in it) and a nuclear molecule on its surface. From analysis of experimental nuclear binding energies one can find the number of alpha-clusters in the molecule and calculate the nuclear charge radii. It was shown that for isotopes of one Z with growing A the number of alpha-clusters in the molecule decreases to three, which corresponds to the nucleus 12C for even Z and 15N for odd Z, and the specific density of the core binding energy ρgrows and reaches its saturation value. In this paper it is shown that the value ρ=2.55 MeV/fm^3 explains the particular number of excess neutrons in stable nuclei.

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arXiv2008

Binding Energies and Radii of the Nuclei with N >=Z in an Alpha-Cluster Model

Using the surface tension energy put in dependence on the number of alpha-clusters in the core in a phenomenological model representing a nucleus as a core and a nuclear molecule on its surface leads to widening the number of isotopes to be described from the narrow strip of beta-stability to the isotopes with N >= Z. The number of alpha-clusters in the molecule is obtained from the analysis of experimental binding energies and the specific density of the core binding energy ρand the radii are calculated. It is shown that for the isotopes of one Z with growing A the number of alpha-clusters of the molecule decreases mostly to 3 and ρincreases to reach a saturation value within ρ= 2.5 ÷2.7 MeV/fm^3 at the beta - stable isotopes, so the narrow strip of the binding energies of the beta - stable isotopes with Z <= 84 is outlined by a function of one variable Z.

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arXiv2007

Specific Density Of Binding Enerfy Of Core In Beta - Stable Nuclei is 2.57 MeV/fm^3

Recently an alpha-cluster model based on the pn-pair interactions with using the isospin invariance of nuclear force has been proposed. According to the model the excess neutron pairs fill out the free space in the core determined by the difference in the charge and matter radii of the alpha-clusters. Then the number of excess neutrons in beta-stable nuclei depends on the number of the core alpha-clusters. In such a representation the specific density of binding energy of core is the only parameter to fit the experimental binding energies of beta-stable nuclei and it turned out to be a constant value equal to 2.57 MeV/fm^3. Knowing the value allows one to estimate the size of a nucleus from its experimental binding energy.

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arXiv2006

Radii and Binding Energies of Nuclei in the Alpha-Cluster Model

The alpha-cluster model is based on two assumptions that the proton-neutron pair interactions are responsible for adherence between alpha-clusters and that the NN-interaction in the alpha-clusters is isospin independent. It allows one to estimate the Coulomb energy and the short range inter-cluster bond energy in dependence on the number of clusters. The charge radii are calculated on the number of alpha-clusters too. Unlike the Weizsacker formula in this model the binding energies of alpha-clusters and excess neutrons are estimated separately. The calculated values are in a good agreement with the experimental data.

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arXiv2005

Charge Radii of beta-Stable Nuclei

In previous work it was shown that the radius of nucleus R is determined by the alpha-cluster structure and can be estimated on the number of alpha-clusters disregarding to the number of excess neutrons. A hypothesis also was made that the radius R_m of a beta-stable isotope, which is actually measured at electron scattering experiments, is determined by the volume occupied by the matter of the core plus the volume occupied by the peripheral alpha-clusters. In this paper it is shown that the condition R_m = R restricts the number of excess neutrons filling the core to provide the beta-stability. The number of peripheral clusters can vary from 1 to 5 and the value of R for heavy nuclei almost do not change, whereas the number of excess neutrons should change with the number of peripheral clusters to get the value of R_m close to R. It can explain the path of the beta-stability and its width. The radii R_m of the stable isotopes with 12 =< Z =< 83 and the alpha-decay isotopes with 84 =< Z =< 116 that are stable to beta-decay have been calculated.

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arXiv2005

Radii and Binding Energies of Nuclei from a Model of the pn-pair Interactions

New formulas to calculate the nuclear charge radii and the nuclear binding energies have been derived in the framework of an alpha-cluster model. The particular features of the model are two assumptions that the proton-neutron pair interactions are responsible for adherence between alpha-clusters and that the proton and the neutron from a proton-neutron pair have equal nuclear potentials. These assumptions allow one to determine the charge and Coulomb radii in dependence on the amount of proton-neutron pairs in the nucleus. Unlike the Weizsacker's formula to calculate nuclear binding energies, in the model the binding energies of alpha-clusters and excess neutrons are estimated separately. The calculated values are in a good agreement with the experimental data.

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