The structures of the nuclei on the alpha-decay chain of ^194Rn are investigated in the deformed relativistic mean-field theory with the effective interaction TMA. We put an emphasis on the ground state properties of ...The structures of the nuclei on the alpha-decay chain of ^194Rn are investigated in the deformed relativistic mean-field theory with the effective interaction TMA. We put an emphasis on the ground state properties of ^194Rn. The calculated alpha-decay energies and lifetimes are both very close to the experimental data for ^186Pb and ^190Po. For ^194Rn, the deviations are a little large on both the alpha-decay energy and the lifetime. We also calculate the alpha-decay energies for the isotopes 192～208^Rn. The tendency for the change of the alpha-decay energies with neutron number is correctly reproduced in the relativistic mean-field theory （RMF）. In general, the RMF theory can give a good description of the alpha decay chain of ^194Rn.展开更多
The newly synthesized element 117 and its alpha-decay chains are systematically investigated in the framework of the relativistic mean field theory with parameter sets NL-Z2 and TMA. The ground-state properties of the...The newly synthesized element 117 and its alpha-decay chains are systematically investigated in the framework of the relativistic mean field theory with parameter sets NL-Z2 and TMA. The ground-state properties of the superheavy nuclei on the alpha-decay chains of 294 117 and 293 117 are calculated. The experimental alpha-decay energies and ha Jr-lives of the two alpha-decay chains are reasonably reproduced by the model The detailed discussions on the binding energies, alpha-decay energies, half-lives, quadrupole deformations, potential energy curves, and single particle levels of the two alpha-decay chains are made.展开更多
A systematic study on the a-decay half-lives of nuclei in the range 93≤Z≤118 is performed by employing various versions of proximity potentials.To obtain more reliable results,deformation terms are included up to he...A systematic study on the a-decay half-lives of nuclei in the range 93≤Z≤118 is performed by employing various versions of proximity potentials.To obtain more reliable results,deformation terms are included up to hexadecapole(β_(4))in the spherical-deformed nuclear and Coulomb interaction potentials.First,the favored a-de-cay processes in this region are categorized as even-even,odd A,and odd-odd nuclei.Second,they are grouped into two transitions:ground state to ground state and ground state to isomeric states.Owing to the comparison of their root-mean-square deviations(RMSD's),Bassll and Ngo80 have the lowest values and better reproduce experimental data.Moreover,by considering preformation probability within the cluster formation model,the results validate the significant reduction in root-mean-square deviations obtained for different versions of proximity.Hence,the deviation between the calculated and experimental data is detracted.展开更多
We present a systematic calculation on the α-decay branching ratios to excited-states of an even-even α-decay chain ^242Cm → ^238Pu → ^234U → ^230Th → ^226Rn by the improved barrier penetration approach. The c...We present a systematic calculation on the α-decay branching ratios to excited-states of an even-even α-decay chain ^242Cm → ^238Pu → ^234U → ^230Th → ^226Rn by the improved barrier penetration approach. The changes of the parities between the parent nuclei and the daughter nuclei are properly taken into account. The theoretical values are compared with the available experimental data and the deviation between them is within a factor of 5 in most cases.展开更多
To search for new candidates of the true and simultaneous two-proton(2 p)radioactivity,the 2 p decay energies(Q2 p)are extracted by the Weizs?cker–Skyrme-4(WS4)model,the finite-range droplet model(FRDM),the Koura–Ta...To search for new candidates of the true and simultaneous two-proton(2 p)radioactivity,the 2 p decay energies(Q2 p)are extracted by the Weizs?cker–Skyrme-4(WS4)model,the finite-range droplet model(FRDM),the Koura–Tachibana–Uno–Yamada(KTUY)model and the Hartree–Fock–Bogoliubov mean-field model with the BSk29 Skyrme interaction(HFB29).Then,the 2 p radioactivity half-lives are calculated within the generalized liquid drop model by inputting the four types of Q2 pvalues.By the energy and half-life constraints,it is found that the probable 2 p decay candidates are the nuclei beyond the proton-drip line in the region of Z≤50 based on the WS4 and KTUY mass models.For the FRDM mass model,the probable 2 p decay candidates are found in the region of Z≤44.However,the 2p-decaying candidates are predicted in the region of Z≤58 by the HFB29 mass model.It means that the probable 2 p decay candidates of Z>50 are only predicted by the HFB29 mass model.Finally,the competition between the true 2p radioactivity andα-decay for the nuclei above the N=Z=50 shell closures is discussed.It is shown that~(101)Te,~(111)Ba and~(114)Ce prefer to 2p radioactivity and the dominant decay mode of~(107)Xe and~(116)Ce isα-decay.展开更多
The two-neutron separation energies(S2n)andα-decay energies(Qα)of the Z=114 isotopes are calculated by the deformed Skyrme-Hartree-Fock-Bogoliubov(SHFB)approach with the SLy5,T22,T32 and T43 interactions.It is found...The two-neutron separation energies(S2n)andα-decay energies(Qα)of the Z=114 isotopes are calculated by the deformed Skyrme-Hartree-Fock-Bogoliubov(SHFB)approach with the SLy5,T22,T32 and T43 interactions.It is found that the tensor force effect on the bulk properties is weak and the shell closure at N=184 is seen evidently with these interactions by analyzing the S2n and Qαevolutions with neutron number N.Meanwhile,the single-particle energy spectra of 298114 are studied using the spherical SHFB approach with these interactions to furthermore examine the shell structure of the magic nucleus 298114.It is shown that the shell structure is almost not changed by the inclusion of the tensor force in the Skyrme interactions.Finally,by examining the energy splitting of the three pairs of pseudospin partners for the protons and neutrons of 298114,it is concluded that the pseudospin symmetry of the neutron states is preserved better than that of the proton states and not all of the pseudospin symmetries of the proton and neutron states are influenced by the tensor force.展开更多
We investigate the formation distance(R0)from the center of the radioactive parent nucleus at which the emitted cluster is most probably formed.The calculations are performed microscopically starting with the solution...We investigate the formation distance(R0)from the center of the radioactive parent nucleus at which the emitted cluster is most probably formed.The calculations are performed microscopically starting with the solution to the time-independent Schr?dinger wave equation for the cluster-core system,using nuclear potentials based on the Skyrme-SLy4 nucleon-nucleon interactions and folding Coulomb potential,to determine the incident and transmitted wave functions of the system.Our results show that the emitted cluster is mostly formed in the pre-surface region of the nucleus,under the effect of Pauli blocking from the saturated core density.The deeperα-formation distance inside the nucleus allows less preformation probability and indicates a more stable nucleus for a longer half-life.Furthermore,theα-particle tends to be formed at a slightly deeper region inside the nuclei,with larger isospin asymmetry,and in the closed shell nuclei.Regarding the heavy clusters,we observed that the formation distance of the emitted clusters heavier thanα-particle increased via increasing the isospin asymmetry of the formed cluster rather than by increasing its mass number.The partial half-life of a certain cluster-decay mode increased with increase of either the mass number or the isospin asymmetry of the emitted cluster.展开更多
基金the Natural Science Foundation of High Education of Anhui Province for Youths under Grant No.2006jq1076the Natural Science Foundation of Anhui Educational Committee under Grant Nos.2006KJ056C and 2006KJ259B+2 种基金National Natural Science Foundation of China under Grant Nos.10475001 and 10675001the Program for New Century Excellent Talents in Universities of China under Grant No.NCET-05-0558the Program for Excellent Talents in Universities of Anhui Province
文摘The structures of the nuclei on the alpha-decay chain of ^194Rn are investigated in the deformed relativistic mean-field theory with the effective interaction TMA. We put an emphasis on the ground state properties of ^194Rn. The calculated alpha-decay energies and lifetimes are both very close to the experimental data for ^186Pb and ^190Po. For ^194Rn, the deviations are a little large on both the alpha-decay energy and the lifetime. We also calculate the alpha-decay energies for the isotopes 192～208^Rn. The tendency for the change of the alpha-decay energies with neutron number is correctly reproduced in the relativistic mean-field theory （RMF）. In general, the RMF theory can give a good description of the alpha decay chain of ^194Rn.
基金Supported by National Natural Science Foundation of China under Grant Nos. 10735010, 10975072, and 11035001, by 973 National Major State Basic Research and Development of China under Grant No. 2007CB815004 and 2010CB327803, CAS Knowledge Innovation Project under Grant No. KJCX2-SW-N02, and by Research Fund of Doctoral Point under Grant No. 20100091110028
文摘The newly synthesized element 117 and its alpha-decay chains are systematically investigated in the framework of the relativistic mean field theory with parameter sets NL-Z2 and TMA. The ground-state properties of the superheavy nuclei on the alpha-decay chains of 294 117 and 293 117 are calculated. The experimental alpha-decay energies and ha Jr-lives of the two alpha-decay chains are reasonably reproduced by the model The detailed discussions on the binding energies, alpha-decay energies, half-lives, quadrupole deformations, potential energy curves, and single particle levels of the two alpha-decay chains are made.
文摘A systematic study on the a-decay half-lives of nuclei in the range 93≤Z≤118 is performed by employing various versions of proximity potentials.To obtain more reliable results,deformation terms are included up to hexadecapole(β_(4))in the spherical-deformed nuclear and Coulomb interaction potentials.First,the favored a-de-cay processes in this region are categorized as even-even,odd A,and odd-odd nuclei.Second,they are grouped into two transitions:ground state to ground state and ground state to isomeric states.Owing to the comparison of their root-mean-square deviations(RMSD's),Bassll and Ngo80 have the lowest values and better reproduce experimental data.Moreover,by considering preformation probability within the cluster formation model,the results validate the significant reduction in root-mean-square deviations obtained for different versions of proximity.Hence,the deviation between the calculated and experimental data is detracted.
基金Supported by National Natural Science Foundation of China (10535010, 10805026, 10775068, 10735010)Major State Basic Research Development Program (2007CB815004)Doctoral Fund of Ministry of Education of China (20070284016)
文摘We present a systematic calculation on the α-decay branching ratios to excited-states of an even-even α-decay chain ^242Cm → ^238Pu → ^234U → ^230Th → ^226Rn by the improved barrier penetration approach. The changes of the parities between the parent nuclei and the daughter nuclei are properly taken into account. The theoretical values are compared with the available experimental data and the deviation between them is within a factor of 5 in most cases.
基金supported by the National Natural Science Foundation of China(Grants No.U1832120 and No.11675265)the Natural Science Foundation for Outstanding Young Scholars of Hebei Province of China(Grants No.A2020210012 and A2018210146)+1 种基金the Continuous Basic Scientific Research Project(Grant No.WDJC-2019-13)the Leading Innovation Project(Grant No.LC 192209000701)。
文摘To search for new candidates of the true and simultaneous two-proton(2 p)radioactivity,the 2 p decay energies(Q2 p)are extracted by the Weizs?cker–Skyrme-4(WS4)model,the finite-range droplet model(FRDM),the Koura–Tachibana–Uno–Yamada(KTUY)model and the Hartree–Fock–Bogoliubov mean-field model with the BSk29 Skyrme interaction(HFB29).Then,the 2 p radioactivity half-lives are calculated within the generalized liquid drop model by inputting the four types of Q2 pvalues.By the energy and half-life constraints,it is found that the probable 2 p decay candidates are the nuclei beyond the proton-drip line in the region of Z≤50 based on the WS4 and KTUY mass models.For the FRDM mass model,the probable 2 p decay candidates are found in the region of Z≤44.However,the 2p-decaying candidates are predicted in the region of Z≤58 by the HFB29 mass model.It means that the probable 2 p decay candidates of Z>50 are only predicted by the HFB29 mass model.Finally,the competition between the true 2p radioactivity andα-decay for the nuclei above the N=Z=50 shell closures is discussed.It is shown that~(101)Te,~(111)Ba and~(114)Ce prefer to 2p radioactivity and the dominant decay mode of~(107)Xe and~(116)Ce isα-decay.
基金supported by the National Natural Science Foundation of China(Grants No.U1832120 and No.11675265)the Natural Science Foundation for Outstanding Young Scholars of Hebei Province of China(Grant No.A2018210146)the Continuous Basic Scientific Research Project(Grant No.WDJC-2019-13).
文摘The two-neutron separation energies(S2n)andα-decay energies(Qα)of the Z=114 isotopes are calculated by the deformed Skyrme-Hartree-Fock-Bogoliubov(SHFB)approach with the SLy5,T22,T32 and T43 interactions.It is found that the tensor force effect on the bulk properties is weak and the shell closure at N=184 is seen evidently with these interactions by analyzing the S2n and Qαevolutions with neutron number N.Meanwhile,the single-particle energy spectra of 298114 are studied using the spherical SHFB approach with these interactions to furthermore examine the shell structure of the magic nucleus 298114.It is shown that the shell structure is almost not changed by the inclusion of the tensor force in the Skyrme interactions.Finally,by examining the energy splitting of the three pairs of pseudospin partners for the protons and neutrons of 298114,it is concluded that the pseudospin symmetry of the neutron states is preserved better than that of the proton states and not all of the pseudospin symmetries of the proton and neutron states are influenced by the tensor force.
文摘We investigate the formation distance(R0)from the center of the radioactive parent nucleus at which the emitted cluster is most probably formed.The calculations are performed microscopically starting with the solution to the time-independent Schr?dinger wave equation for the cluster-core system,using nuclear potentials based on the Skyrme-SLy4 nucleon-nucleon interactions and folding Coulomb potential,to determine the incident and transmitted wave functions of the system.Our results show that the emitted cluster is mostly formed in the pre-surface region of the nucleus,under the effect of Pauli blocking from the saturated core density.The deeperα-formation distance inside the nucleus allows less preformation probability and indicates a more stable nucleus for a longer half-life.Furthermore,theα-particle tends to be formed at a slightly deeper region inside the nuclei,with larger isospin asymmetry,and in the closed shell nuclei.Regarding the heavy clusters,we observed that the formation distance of the emitted clusters heavier thanα-particle increased via increasing the isospin asymmetry of the formed cluster rather than by increasing its mass number.The partial half-life of a certain cluster-decay mode increased with increase of either the mass number or the isospin asymmetry of the emitted cluster.
