We investigate the effect of isotropic velocity-dependent potentials on the bound state energy eigenvalues for the first time for any quantum states of the Coulomb and harmonic oscillator potentials within the framewo...We investigate the effect of isotropic velocity-dependent potentials on the bound state energy eigenvalues for the first time for any quantum states of the Coulomb and harmonic oscillator potentials within the framework of the asymptotic iteration method.When the velocity-dependent term is selected as a constant parameter𝜌0,we present that the energy eigenvalues can be obtained analytically for both Coulomb and harmonic oscillator potentials.However,when the velocity-dependent term is considered as a harmonic oscillator type𝜌ρor^(2)𝑟,taking the velocity-dependent term as a perturbation,we present how to obtain the energy eigenvalues of the Coulomb and harmonic oscillator potentials for any n and e quantum states by using perturbation expansion and numerical calculations in the asymptotic iteration method procedure.展开更多
The dependence of proton emission half-lives on the nuclear asymmetry parameter is investigated using the WKB method and two types of empirical formula.Using the single-folding formalism with asymmetry-depend-ent nucl...The dependence of proton emission half-lives on the nuclear asymmetry parameter is investigated using the WKB method and two types of empirical formula.Using the single-folding formalism with asymmetry-depend-ent nuclear radius and surface diffuseness of nuclear matter,the nuclear potential and consequently the half-life are functions of the asymmetry factor.Despite small values of asymmetry in neutron-deficient proton emitters,notice-able changes in the half-lives are observed.The addition of an asymmetry parameter term to the two forms of empir-ical formulas leads to a reduction in the rms error for ground state and isomeric transitions.A noticeable reduction of about 43%is obtained for isomeric transitions in the second form of the empirical formula.Considering ground state transitions in two categories,odd-even and odd-odd emitters,and adopting deformation and asymmetry-dependent empirical formulas,the rms decreases remarkably.The low est values of rms errors,viz.0.1492,0.2312,and 0.1999,are obtained for the aforementioned empirical formulas for ground state transitions of odd-even and odd-odd emit-ters and for all isomeric transitions,respectively.展开更多
Spontaneous fission(SF) with a new formula based on a liquid drop model is proposed and used in the calculation of the SF half-lives of heavy and superheavy nuclei(Z = 90–120). The predicted half-lives are in agreeme...Spontaneous fission(SF) with a new formula based on a liquid drop model is proposed and used in the calculation of the SF half-lives of heavy and superheavy nuclei(Z = 90–120). The predicted half-lives are in agreement with the experimental SF half-lives. The half-lives of decay(AD) for the same nuclei are obtained by using the Wentzel-Kramers-Brillouin(WKB) method together with Bohr-Sommerfeld(BS) quantization condition considering the isospin-dependent effects for the cosh potential. The decay modes and branching ratios of superheavy nuclei(Z =104-118) with experimental decay modes are obtained, and the modes are compared with the experimental ones and with the predictions found in the literature. Although some nuclei have predicted decay modes that are different from their experimental decay modes, decay modes same as the experimental ones are predicted for many nuclei. The SF and AD half-lives, branching ratios, and decay modes are obtained for superheavy nuclei(Z = 119–120) with unknown decay modes and compared with the predictions obtained in a previous study. The present results provide useful information for future experimental studies performed on both the AD and SF of superheavy nuclei.展开更多
By adopting different neutron and proton density distributions,cluster decay half-lives were investigated using double-folding potentials with constant and nuclear asymmetry dependent sets of nuclear density parameter...By adopting different neutron and proton density distributions,cluster decay half-lives were investigated using double-folding potentials with constant and nuclear asymmetry dependent sets of nuclear density parameters.Two adopted asymmetry dependent sets of parameters were fitted based on microscopic calculations,and they were calculated based on the neutron skin/halo-type nuclei assumption and by employing experimental rms charge radii.A bulk agreement between theory and experiment was obtained for all sets of parameters using a calculated cluster preformation probability.Few differences were observed between the skin and halo-type assumptions.However,the notable role of the asymmetry parameter was observed in the relatively large differences between the skin and skintype with zero thickness.展开更多
One of the important reactions for nucleosynthesis in the carbon burning phase in high-mass stars is the12C+12C fusion reaction. In this study, we investigate the influences of the nuclear potentials and screening eff...One of the important reactions for nucleosynthesis in the carbon burning phase in high-mass stars is the12C+12C fusion reaction. In this study, we investigate the influences of the nuclear potentials and screening effect on astrophysically interesting12C+12C fusion reaction observables at sub-barrier energies by using the microscopic α-αdouble folding cluster(DFC) potential and the proximity potential. In order to model the screening effects on the experimental data, a more general exponential cosine screened Coulomb(MGECSC) potential including Debye and quantum plasma cases has been considered in the calculations for the12C+12C fusion reaction. In the calculations of the reaction observables, the semi-classical Wentzel-Kramers-Brillouin(WKB) approach and coupled channel(CC)formalism have been used. Moreover, in order to investigate how the potentials between12C nuclei produce molecular cluster states of24Mg, the normalized resonant energy states of24Mg cluster bands have been calculated for the DFC potential. By analyzing the results produced from the fusion of12C+12C, it is found that taking into account the screening effects in terms of MGECSC is important for explaining the12C+12C fusion data, and the microscopic DFC potential is better than the proximity potential in explaining the experimental data, also considering that clustering is dominant for the structure of the24Mg nucleus.展开更多
基金Partially supported by the Turkish Science and Research Council(TÜBİTAK)under Grant Nos 109T373 and 210T155,the Turkish Academy of Sciences(TÜBA-GEBİP),Akdeniz University Scientific Research Projects Unit.O.Bayrak and A.Soylu acknowledge the financial support of TÜBİTAK-BİDEP.
文摘We investigate the effect of isotropic velocity-dependent potentials on the bound state energy eigenvalues for the first time for any quantum states of the Coulomb and harmonic oscillator potentials within the framework of the asymptotic iteration method.When the velocity-dependent term is selected as a constant parameter𝜌0,we present that the energy eigenvalues can be obtained analytically for both Coulomb and harmonic oscillator potentials.However,when the velocity-dependent term is considered as a harmonic oscillator type𝜌ρor^(2)𝑟,taking the velocity-dependent term as a perturbation,we present how to obtain the energy eigenvalues of the Coulomb and harmonic oscillator potentials for any n and e quantum states by using perturbation expansion and numerical calculations in the asymptotic iteration method procedure.
文摘The dependence of proton emission half-lives on the nuclear asymmetry parameter is investigated using the WKB method and two types of empirical formula.Using the single-folding formalism with asymmetry-depend-ent nuclear radius and surface diffuseness of nuclear matter,the nuclear potential and consequently the half-life are functions of the asymmetry factor.Despite small values of asymmetry in neutron-deficient proton emitters,notice-able changes in the half-lives are observed.The addition of an asymmetry parameter term to the two forms of empir-ical formulas leads to a reduction in the rms error for ground state and isomeric transitions.A noticeable reduction of about 43%is obtained for isomeric transitions in the second form of the empirical formula.Considering ground state transitions in two categories,odd-even and odd-odd emitters,and adopting deformation and asymmetry-dependent empirical formulas,the rms decreases remarkably.The low est values of rms errors,viz.0.1492,0.2312,and 0.1999,are obtained for the aforementioned empirical formulas for ground state transitions of odd-even and odd-odd emit-ters and for all isomeric transitions,respectively.
基金Supported by the Turkish Science and Research Council(TüB?TAK)with Grant Number 118R028
文摘Spontaneous fission(SF) with a new formula based on a liquid drop model is proposed and used in the calculation of the SF half-lives of heavy and superheavy nuclei(Z = 90–120). The predicted half-lives are in agreement with the experimental SF half-lives. The half-lives of decay(AD) for the same nuclei are obtained by using the Wentzel-Kramers-Brillouin(WKB) method together with Bohr-Sommerfeld(BS) quantization condition considering the isospin-dependent effects for the cosh potential. The decay modes and branching ratios of superheavy nuclei(Z =104-118) with experimental decay modes are obtained, and the modes are compared with the experimental ones and with the predictions found in the literature. Although some nuclei have predicted decay modes that are different from their experimental decay modes, decay modes same as the experimental ones are predicted for many nuclei. The SF and AD half-lives, branching ratios, and decay modes are obtained for superheavy nuclei(Z = 119–120) with unknown decay modes and compared with the predictions obtained in a previous study. The present results provide useful information for future experimental studies performed on both the AD and SF of superheavy nuclei.
文摘By adopting different neutron and proton density distributions,cluster decay half-lives were investigated using double-folding potentials with constant and nuclear asymmetry dependent sets of nuclear density parameters.Two adopted asymmetry dependent sets of parameters were fitted based on microscopic calculations,and they were calculated based on the neutron skin/halo-type nuclei assumption and by employing experimental rms charge radii.A bulk agreement between theory and experiment was obtained for all sets of parameters using a calculated cluster preformation probability.Few differences were observed between the skin and halo-type assumptions.However,the notable role of the asymmetry parameter was observed in the relatively large differences between the skin and skintype with zero thickness.
基金Supported by the Turkish Science and Research Council (TüBIiTAK) with (117R015)
文摘One of the important reactions for nucleosynthesis in the carbon burning phase in high-mass stars is the12C+12C fusion reaction. In this study, we investigate the influences of the nuclear potentials and screening effect on astrophysically interesting12C+12C fusion reaction observables at sub-barrier energies by using the microscopic α-αdouble folding cluster(DFC) potential and the proximity potential. In order to model the screening effects on the experimental data, a more general exponential cosine screened Coulomb(MGECSC) potential including Debye and quantum plasma cases has been considered in the calculations for the12C+12C fusion reaction. In the calculations of the reaction observables, the semi-classical Wentzel-Kramers-Brillouin(WKB) approach and coupled channel(CC)formalism have been used. Moreover, in order to investigate how the potentials between12C nuclei produce molecular cluster states of24Mg, the normalized resonant energy states of24Mg cluster bands have been calculated for the DFC potential. By analyzing the results produced from the fusion of12C+12C, it is found that taking into account the screening effects in terms of MGECSC is important for explaining the12C+12C fusion data, and the microscopic DFC potential is better than the proximity potential in explaining the experimental data, also considering that clustering is dominant for the structure of the24Mg nucleus.
