The ground state properties of the spherical nucleus ^40Ca have been investigated by using constrained spherical Hartree Fock （CSHF） approximation at equilibrium and under high radial compression in a six major shel...The ground state properties of the spherical nucleus ^40Ca have been investigated by using constrained spherical Hartree Fock （CSHF） approximation at equilibrium and under high radial compression in a six major shells. The effective baryon-baryon interaction that includes the △（1236） resonance freedom degrees to calculate nuclear properties is used. The nucleon-nucleon （N-N） interaction is based on Reid soft core （RSC） potential. The results of calculations show that much of increase in the nuclear energy generated under compression is used to create the massive △ particles. The number of △ ＇s can be increased to about 2.1% of constituents of nucleus when nuclear density reaches about 1.34 times of normal density. The single particle energy levels are calculated and their behavior under compression is also examined. △ good agreement has been found between current calculations and phenomenological shell model for low lying single-particle spectra. The gap between shells is very clear and L-S coupling become stronger as increasing the static load on the nucleus. The results show a considerable reduction in compressibility when freedom degrees of △＇s are taken into account. It has been found that the total nuclear radial density becomes denser in the interior and less dense in the exterior region of nucleus. The surface of nucleus becomes more and more responsive to compression than outer region.展开更多
Constrained spherical Hartree-Fock (CSHF) calculations under radial compression are presented for <sup>90</sup>Zr in a model space consisting of nine major oscillator shells. An effective baryon-baryon int...Constrained spherical Hartree-Fock (CSHF) calculations under radial compression are presented for <sup>90</sup>Zr in a model space consisting of nine major oscillator shells. An effective baryon-baryon interaction which includes the Δ resonances is used. The nucleon-nucleon (N-N) interaction is Reid Soft Core (RSC) potential. The sensitivity of the results to the choice model space is examined. It is found that the nuclear system becomes more compressible when the model space is increased. The radial density and the number of Δs are decreased by increasing model space. The results suggest that the behavior of single particle energies is independent of the model space.展开更多
A non-relativistic microscopic mean field theory of finite nuclei is investigated where the nucleus is described as a collection of nucleons and delta resonances. The ground state properties of 90Zr nucleus have been ...A non-relativistic microscopic mean field theory of finite nuclei is investigated where the nucleus is described as a collection of nucleons and delta resonances. The ground state properties of 90Zr nucleus have been investigated at equilibrium and large amplitude compression using a realistic effective baryon-baryon Hamiltonian based on Reid Soft Core （RSC） potential. The sensitivity of the ground state properties is studied, such as binding energy, nuclear radius, radial density distribution, and single particle energies to the degree of compression. It is found that the most of increasing in the nuclear energy generated under compression is used to create the massive Δ particles. For 90Zr nucleus under compression at 2.5 times density of the normal nuclear density, the excited nucleons to Δ ＇s are increased sharply up to 14% of the total number of constituents. This result is consistent with the values extracted from relativistic heavy-ion collisions. The single particle energy levels are calculated and their behaviors under compression are examined too. A good agreement between results with effective Hamiltonian and the phenomenologieal shell model for the low lying single-particle spectra is obtained. A considerable reduction in compressibility for the nucleus, and softening of the equation of state with the inclusion of the Δ＇s in the nuclear dynamics are suggested by the results.展开更多
Recently near-edge X-ray absorption fine structure (NEXAFS) has become an important method for surface structure analysing because it offers the information of intramolecular bond-length and molecular orientation for ...Recently near-edge X-ray absorption fine structure (NEXAFS) has become an important method for surface structure analysing because it offers the information of intramolecular bond-length and molecular orientation for molecule adsorbate-substrate systems.展开更多
The ground state properties of 132Sn at equilibrium and at large compression are investigated,within the framework of the radially constrained spherical Hartree-Fock(CSHF)approximation.The delta resonance effects on t...The ground state properties of 132Sn at equilibrium and at large compression are investigated,within the framework of the radially constrained spherical Hartree-Fock(CSHF)approximation.The delta resonance effects on the properties of neutron-rich double magic spherical nucleus,132Sn,in its ground state and the state under static compression are studied.The sensitivity of the nucleon size and Δ model spaces is investigated.At equilibrium,mixing between nucleon and Δ's in the largest model space of nine major nucleon shells plus 10 Δ orbitals was found.Expanding the nucleon model space has a larger effect on reducing the static compression modulus and softe-ning the nuclear equation of state than increasing the number of Δ states.It was found that the most of the increase in the nuclear energy generated under compression is used to create the massive Δ particles.For 132Sn nucleus under compression at 12 times the normal nuclear density,the excited nucleons to Δ's increased sharply up to 13% of the total number of constituents.This result is consistent with the values extracted from relativistic heavy-ion collisions.The single particle energy levels calculated and their behaviors under compression are examined too.A good agreement between results with effective Hamiltonian and the phenomenological shell model for the low lying single-particle spectra is obtained.展开更多
With an oscillator basis,the nuclear Hamiltonian is defined in a no-core model space.It consists of an effective nucleon-nucleon interaction obtained with Brueckner theory from the Reid soft core interaction,a Coulomb...With an oscillator basis,the nuclear Hamiltonian is defined in a no-core model space.It consists of an effective nucleon-nucleon interaction obtained with Brueckner theory from the Reid soft core interaction,a Coulomb potential,nucleon-delta transition potentials,and delta-delta interaction terms.By performing spherical Hartree-Fock(SHF) calculations with the realistic baryon Hamiltonian,the ground state properties of 40Ca are studied.For an estimate of how the delta degree of freedom is excited,SHF calculations are performed with a radial constraint to compress the nucleus.The delta degree of freedom is gradually populated as the nucleus is compressed.The number of Δ's is decreased by increasing model space.Large amount of the compressive energy is delivered to create massive Δ in the nucleus.There is a significant reduction in the static compression modulus for RSC static compressions which is reduced by including the Δ excitations.The static compression modulus is decreased significantly by en larging the nucleon model space.The results suggest that inclusion of the delta in the nuclear dynamics could head to a significant softening of the nuclear equation of state.展开更多
文摘The ground state properties of the spherical nucleus ^40Ca have been investigated by using constrained spherical Hartree Fock （CSHF） approximation at equilibrium and under high radial compression in a six major shells. The effective baryon-baryon interaction that includes the △（1236） resonance freedom degrees to calculate nuclear properties is used. The nucleon-nucleon （N-N） interaction is based on Reid soft core （RSC） potential. The results of calculations show that much of increase in the nuclear energy generated under compression is used to create the massive △ particles. The number of △ ＇s can be increased to about 2.1% of constituents of nucleus when nuclear density reaches about 1.34 times of normal density. The single particle energy levels are calculated and their behavior under compression is also examined. △ good agreement has been found between current calculations and phenomenological shell model for low lying single-particle spectra. The gap between shells is very clear and L-S coupling become stronger as increasing the static load on the nucleus. The results show a considerable reduction in compressibility when freedom degrees of △＇s are taken into account. It has been found that the total nuclear radial density becomes denser in the interior and less dense in the exterior region of nucleus. The surface of nucleus becomes more and more responsive to compression than outer region.
文摘Constrained spherical Hartree-Fock (CSHF) calculations under radial compression are presented for <sup>90</sup>Zr in a model space consisting of nine major oscillator shells. An effective baryon-baryon interaction which includes the Δ resonances is used. The nucleon-nucleon (N-N) interaction is Reid Soft Core (RSC) potential. The sensitivity of the results to the choice model space is examined. It is found that the nuclear system becomes more compressible when the model space is increased. The radial density and the number of Δs are decreased by increasing model space. The results suggest that the behavior of single particle energies is independent of the model space.
文摘A non-relativistic microscopic mean field theory of finite nuclei is investigated where the nucleus is described as a collection of nucleons and delta resonances. The ground state properties of 90Zr nucleus have been investigated at equilibrium and large amplitude compression using a realistic effective baryon-baryon Hamiltonian based on Reid Soft Core （RSC） potential. The sensitivity of the ground state properties is studied, such as binding energy, nuclear radius, radial density distribution, and single particle energies to the degree of compression. It is found that the most of increasing in the nuclear energy generated under compression is used to create the massive Δ particles. For 90Zr nucleus under compression at 2.5 times density of the normal nuclear density, the excited nucleons to Δ ＇s are increased sharply up to 14% of the total number of constituents. This result is consistent with the values extracted from relativistic heavy-ion collisions. The single particle energy levels are calculated and their behaviors under compression are examined too. A good agreement between results with effective Hamiltonian and the phenomenologieal shell model for the low lying single-particle spectra is obtained. A considerable reduction in compressibility for the nucleus, and softening of the equation of state with the inclusion of the Δ＇s in the nuclear dynamics are suggested by the results.
基金Project supported by the National Natural Science Foundation of China.
文摘Recently near-edge X-ray absorption fine structure (NEXAFS) has become an important method for surface structure analysing because it offers the information of intramolecular bond-length and molecular orientation for molecule adsorbate-substrate systems.
文摘The ground state properties of 132Sn at equilibrium and at large compression are investigated,within the framework of the radially constrained spherical Hartree-Fock(CSHF)approximation.The delta resonance effects on the properties of neutron-rich double magic spherical nucleus,132Sn,in its ground state and the state under static compression are studied.The sensitivity of the nucleon size and Δ model spaces is investigated.At equilibrium,mixing between nucleon and Δ's in the largest model space of nine major nucleon shells plus 10 Δ orbitals was found.Expanding the nucleon model space has a larger effect on reducing the static compression modulus and softe-ning the nuclear equation of state than increasing the number of Δ states.It was found that the most of the increase in the nuclear energy generated under compression is used to create the massive Δ particles.For 132Sn nucleus under compression at 12 times the normal nuclear density,the excited nucleons to Δ's increased sharply up to 13% of the total number of constituents.This result is consistent with the values extracted from relativistic heavy-ion collisions.The single particle energy levels calculated and their behaviors under compression are examined too.A good agreement between results with effective Hamiltonian and the phenomenological shell model for the low lying single-particle spectra is obtained.
文摘With an oscillator basis,the nuclear Hamiltonian is defined in a no-core model space.It consists of an effective nucleon-nucleon interaction obtained with Brueckner theory from the Reid soft core interaction,a Coulomb potential,nucleon-delta transition potentials,and delta-delta interaction terms.By performing spherical Hartree-Fock(SHF) calculations with the realistic baryon Hamiltonian,the ground state properties of 40Ca are studied.For an estimate of how the delta degree of freedom is excited,SHF calculations are performed with a radial constraint to compress the nucleus.The delta degree of freedom is gradually populated as the nucleus is compressed.The number of Δ's is decreased by increasing model space.Large amount of the compressive energy is delivered to create massive Δ in the nucleus.There is a significant reduction in the static compression modulus for RSC static compressions which is reduced by including the Δ excitations.The static compression modulus is decreased significantly by en larging the nucleon model space.The results suggest that inclusion of the delta in the nuclear dynamics could head to a significant softening of the nuclear equation of state.
