Semi-empirical formulae for Λ-binding energy in hypernuclei using mass distribution

Pramana ◽  
1997 ◽  
Vol 48 (5) ◽  
pp. 1027-1034 ◽  
Author(s):  
M Z Rahman Khan ◽  
Nasra Neelofer ◽  
M A Suhail
Keyword(s):  
Binding Energy ◽  
Mass Distribution ◽  
Semi Empirical

Universal origin of heavy elements

2021 ◽  
Author(s):  
Jose Orce ◽  
Balaram Dey ◽  
Cebo Ngwetsheni ◽  
Brenden Lesch ◽  
Andile Zulu ◽  
...  
Keyword(s):  
Binding Energy ◽  
Symmetry Energy ◽  
Neutron Capture ◽  
Decay Rates ◽  
Heavy Elements ◽  
Capture Process ◽  
Atomic Nuclei ◽  
Radiative Neutron ◽  
Radiative Neutron Capture ◽  
Semi Empirical

Abstract The abundance of heavy elements above iron through the rapid neutron capture process or r-process is intimately related to the competition between neutron capture and $\beta$ decay rates, which ultimately depends on the binding energy of atomic nuclei. The well-known Bethe-Weizsacker semi-empirical mass formula describes the binding energy of ground states in nuclei with temperatures of T~0 MeV, where the nuclear symmetry energy saturates between 23-26 MeV. Here we find a larger saturation energy of ~30 MeV for nuclei at T~0.7-1.3 MeV, which corresponds to the typical temperatures where seed elements are created during the cooling down of the ejecta following neutron-star mergers and collapsars. This large symmetry energy yields a reduction of the binding energy per nucleon for neutron-rich nuclei; hence, the close in of the neutron dripline, where nuclei become unbound. This finding constrains exotic paths in the nucleosynthesis of heavy elements -- as supported by microscopic calculations of radiative neutron-capture rates -- and further supports the universal origin of heavy elements, as inferred from the abundances in extremely metal-poor stars and meteorites.

Models of Electron-Hole Screening and Exciton Binding in Conjugated Polymers

1995 ◽  
Vol 413 ◽  
Author(s):  
David Yaron ◽  
Eric Moore ◽  
Benjamin Gherman
Keyword(s):  
Binding Energy ◽  
Conjugated Polymers ◽  
Point Charge ◽  
Solvation Energy ◽  
Exciton Binding Energy ◽  
Electron Interaction ◽  
Electron Hole ◽  
Relative Time ◽  
Hartree Fock ◽  
Semi Empirical

ABSTRACTThe use of semi-empirical quantum chemistry to calculate the exciton binding energy of conjugated polymers is discussed. Both the Pariser-Parr-Pople (PPP) model with Ohno parameterization and the models present in the MOPAC program overestimate the exciton binding energy relative to that observed in solid-state materials. Inclusion of Coulomb screening from adjacent chains may correct this overestimation. The solvation energy of a point charge in polyacetylene is calculated as 0.9eV, using Hartree-Fock theory to describe the polarization induced in the solvent chains. It is argued that including screening by modifying the electron-electron interaction energy of the PPP model introduces physically unreasonable side effects and is not consistent with the 0.9eV solvation energy of a point charge. Electron-hole screening models are then discussed along with the need to consider the relative time scales of the electron-hole motion and the dielectric response.

Semi-Empirical Formulae for Λ and Ξ Binding Energy in Hypernuclei

1986 ◽  
Vol 55 (9) ◽  
pp. 3008-3013 ◽  
Author(s):  
M. Z. Rahman Khan ◽  
M. Shoeb
Keyword(s):  
Binding Energy ◽  
Semi Empirical

scholarly journals On the Role of Squared Neutron Number in Reducing Nuclear Binding Energy in the Light of Electromagnetic, Weak and Nuclear Gravitational Constants – A Review

2019 ◽  
pp. 1-22
Author(s):  
U. V. S. Seshavatharam ◽  
S. Lakshminarayana
Keyword(s):  
Binding Energy ◽  
Strong Coupling ◽  
Mass Formula ◽  
Neutron Number ◽  
Strong Coupling Constant ◽  
Nuclear Binding Energy ◽  
Coupling Constant ◽  
Nuclear Binding ◽  
Energy Coefficient ◽  
Semi Empirical

With reference to authors recently proposed three virtual atomic gravitational constants and nuclear elementary charge, close to stable mass numbers, it is possible to show that, squared neutron number plays a major role in reducing nuclear binding energy. In this context, Z=30 onwards, ‘inverse of the strong coupling constant’, can be inferred as a representation of the maximum strength of nuclear interaction and 10.09 MeV can be considered as a characteristic nuclear binding energy coefficient. Coulombic energy coefficient being 0.695 MeV, semi empirical mass formula - volume, surface, asymmetric and pairing energy coefficients can be shown to be 15.29 MeV, 15.29 MeV, 23.16 MeV and 10.09 MeV respectively. Volume and Surface energy terms can be represented with (A-A2/3-1)*15.29 MeV. With reference to nuclear potential of 1.162 MeV and coulombic energy coefficient, close to stable mass numbers, nuclear binding energy can be fitted with two simple terms having an effective binding energy coefficient of  [10.09-(1.162+0.695)/2] = 9.16 MeV. Nuclear binding energy can also be fitted with five terms having a single energy coefficient of 10.09 MeV. With further study, semi empirical mass formula can be simplified with respect to strong coupling constant.

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