We study radiative p^(15)N capture on the ground state of ^(16)O at stellar energies within the framework of a modified potential cluster model(MPCM)with forbidden states,including low-lying resonances.The investigati...We study radiative p^(15)N capture on the ground state of ^(16)O at stellar energies within the framework of a modified potential cluster model(MPCM)with forbidden states,including low-lying resonances.The investigation of the ^(15)N(p,γ0)^(16)O reaction includes the consideration of ^(3)S_(1) resonances due to E1 transitions and the contribution of the ^(3)P_(1) scattering wave in the p+^(15)N channel due to the ^(3)P_(1)→^(3)P_(0)M1 transition.We calculated the astrophysical low-energy S-factor,and the extrapolated S(0)turned out to be within 34.7−40.4 keV·b.The important role of the asymptotic constant(AC)for the ^(15)N(p,γ0)16O process with interfering ^(3)S_(1)(312)and ^(3)S_(1)(962)resonances is elucidated.A comparison of our calculation for the S-factor with existing experimental and theoretical data is addressed,and a reasonable agreement is found.The reaction rate is calculated and compared with the existing rates.It has negligible dependence on the variation of AC but shows a strong impact of the interference of ^(3)S_(1)(312)and ^(3)S_(1)(962)resonances in reference to the CNO Gamow windows,especially at low temperatures.We estimate the contribution of cascade transitions to the reaction rate based on the exclusive experimental data from Phys.Rev.C.85,065810(2012).The reaction rate enhancement due to the cascade transitions is observed from T_(9)>0.3 and reaches the maximum factor~1.3 at T_(9)=1.3.We present the Gamow energy window and a comparison of rates for radiative proton capture reactions ^(12)N(p,γ)^(13)O,^(13)N(p,γ)^(14)O,^(14)N(p,γ)^(15)O,and ^(15)N(p,γ)^(16)O obtained in the framework of the MPCM and provide the temperature windows,prevalence,and significance of each process.展开更多
We discuss current attempts to employ the modified potential cluster model to describe the available experimental data on the^(13)B(n,γ0+1)^(14)B total cross-sections.The estimated results of the M1 and E1 transition...We discuss current attempts to employ the modified potential cluster model to describe the available experimental data on the^(13)B(n,γ0+1)^(14)B total cross-sections.The estimated results of the M1 and E1 transitions from the n^(13)B scattering states to the ground and first excited states of^(14)B are presented.The 1st resonance at Ex=1.275 MeV(1+)is revealed in both the cross-section and reaction rate.Within the variation in the asymptotic constant,a thermal cross-section interval of 5.1-8.9 mb is proposed.Based on the theoretical total cross-sections at energies of 0.01 eV to 5 MeV,we calculate the reaction rate in the temperature range of 0.01 to 10T9.The ignition T9 values of the^(13)B(n,γ0+1)^(14)B reaction depending on a neutron number density n_(n)of~10^(22)cm^(−3)are determined.The radiative neutron capture reaction rates on the boron^(10-13)B and carbon^(12-14)Сisotopes are compared.展开更多
Within the framework of the modified potential cluster model with forbidden states,the total cross-sections of radiative n^(9)Be capture to the ground and five low-lying excited states are calculated at energies from ...Within the framework of the modified potential cluster model with forbidden states,the total cross-sections of radiative n^(9)Be capture to the ground and five low-lying excited states are calculated at energies from 10^(-2)eV up to 5 MeV.The thermal cross-section σ_(th)=8.35mb is in good agreement with experimental data.We considered five resonances at the excitation energies E_(x)from 7.371 MeV up to 10.570 MeV corresponding to the following states with J^(π)(E_(x),MeV):3^(-)(7.371),2^(+)(7.542),3^(+)(9.4),2^(+)(9.56),and 3^(-)(10.570).The partial and total ^(9)Be(n,γ0+1+2+3+4+5)^(10)Be reaction rates are calculated at temperatures from 0.001 to 10 T_(9).Contrary to the available data,we propose that the rise in the reaction rate near factor five at T_(9)>1 is mainly due to the first 3^(-)(E_(R)=0.559 MeV)resonance.We foresee this contrast as arising from different model approaches.展开更多
基金the Ministry of Science and Higher Education of the Republic of Kazakhstan(AP09259174)。
文摘We study radiative p^(15)N capture on the ground state of ^(16)O at stellar energies within the framework of a modified potential cluster model(MPCM)with forbidden states,including low-lying resonances.The investigation of the ^(15)N(p,γ0)^(16)O reaction includes the consideration of ^(3)S_(1) resonances due to E1 transitions and the contribution of the ^(3)P_(1) scattering wave in the p+^(15)N channel due to the ^(3)P_(1)→^(3)P_(0)M1 transition.We calculated the astrophysical low-energy S-factor,and the extrapolated S(0)turned out to be within 34.7−40.4 keV·b.The important role of the asymptotic constant(AC)for the ^(15)N(p,γ0)16O process with interfering ^(3)S_(1)(312)and ^(3)S_(1)(962)resonances is elucidated.A comparison of our calculation for the S-factor with existing experimental and theoretical data is addressed,and a reasonable agreement is found.The reaction rate is calculated and compared with the existing rates.It has negligible dependence on the variation of AC but shows a strong impact of the interference of ^(3)S_(1)(312)and ^(3)S_(1)(962)resonances in reference to the CNO Gamow windows,especially at low temperatures.We estimate the contribution of cascade transitions to the reaction rate based on the exclusive experimental data from Phys.Rev.C.85,065810(2012).The reaction rate enhancement due to the cascade transitions is observed from T_(9)>0.3 and reaches the maximum factor~1.3 at T_(9)=1.3.We present the Gamow energy window and a comparison of rates for radiative proton capture reactions ^(12)N(p,γ)^(13)O,^(13)N(p,γ)^(14)O,^(14)N(p,γ)^(15)O,and ^(15)N(p,γ)^(16)O obtained in the framework of the MPCM and provide the temperature windows,prevalence,and significance of each process.
基金the Ministry of Science and Higher Education of the Republic of Kazakhstan(AP09259174)。
文摘We discuss current attempts to employ the modified potential cluster model to describe the available experimental data on the^(13)B(n,γ0+1)^(14)B total cross-sections.The estimated results of the M1 and E1 transitions from the n^(13)B scattering states to the ground and first excited states of^(14)B are presented.The 1st resonance at Ex=1.275 MeV(1+)is revealed in both the cross-section and reaction rate.Within the variation in the asymptotic constant,a thermal cross-section interval of 5.1-8.9 mb is proposed.Based on the theoretical total cross-sections at energies of 0.01 eV to 5 MeV,we calculate the reaction rate in the temperature range of 0.01 to 10T9.The ignition T9 values of the^(13)B(n,γ0+1)^(14)B reaction depending on a neutron number density n_(n)of~10^(22)cm^(−3)are determined.The radiative neutron capture reaction rates on the boron^(10-13)B and carbon^(12-14)Сisotopes are compared.
基金Supported by the Ministry of Science and Higher Education of the Republic of Kazakhstan(AP09259021)。
文摘Within the framework of the modified potential cluster model with forbidden states,the total cross-sections of radiative n^(9)Be capture to the ground and five low-lying excited states are calculated at energies from 10^(-2)eV up to 5 MeV.The thermal cross-section σ_(th)=8.35mb is in good agreement with experimental data.We considered five resonances at the excitation energies E_(x)from 7.371 MeV up to 10.570 MeV corresponding to the following states with J^(π)(E_(x),MeV):3^(-)(7.371),2^(+)(7.542),3^(+)(9.4),2^(+)(9.56),and 3^(-)(10.570).The partial and total ^(9)Be(n,γ0+1+2+3+4+5)^(10)Be reaction rates are calculated at temperatures from 0.001 to 10 T_(9).Contrary to the available data,we propose that the rise in the reaction rate near factor five at T_(9)>1 is mainly due to the first 3^(-)(E_(R)=0.559 MeV)resonance.We foresee this contrast as arising from different model approaches.
