共查询到20条相似文献,搜索用时 218 毫秒
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16O+16O弹性散射在124MeV能量下最新的全角区的实验角分布,可以被建立在16O的α结构基础上的折叠模型很好地再现. 相似文献
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利用质子散射作为手段对16O的α粒子结构模型进行了检验.基于4α结构模型,对跨度整个中能区的质子与16O核的弹性角分布进行了无自由参数的计算.理论与实验基本符合. 相似文献
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正在研制的上海激光电子γ源是MeV量级的高品质γ光束线站,基于该装置可以开展一系列核天体物理实验, 从而更准确的确定各天体核合成反应的反应率. 本文研究了天体核合成中的关键反应12C(α,γ)16O的反应率. 根据多组实验和理论截面数据分别计算了反应率, 并给出了这些反应率计算结果的平均值和统计误差. 根据该结果拟合了理论反应率的解析形式, 确定了新的参数. 进而给出俘获反应12C(α,γ)16O在He燃烧环境下的反应率和误差, 并讨论了电子屏蔽效应对天体反应率的修正. 相似文献
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使用Monte-Carlo模拟计算了垒下16O+232Th系统转移裂变和复合核裂变碎片角分布及角关联.转移过程、熔合过程和裂变过程分别用半经典模型、耦合道模型及鞍点过渡态统计模型进行模拟.考虑了各物理量分布产生的运动学效应及裂前中子发射和裂后碎片粒子蒸发对碎片角分布及角关联的影响.模拟结果和实验测量的分布相一致.使用折叠角技术借助Monte-Carlo模拟区分转移裂变和复合核裂变是可能的.考虑了转移裂变和裂前中子发射的影响,复合核裂变碎片角分布各向异性异常仍然存在. 相似文献
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本文从唯象的Λ-α相互作用位和12C、16O的独立α粒子模型波函数出发,采用折迭位方法,求出了Λ-12C、Λ-16O等效相互作用位的解析表示,在此基础上计算了超核13C、17O的低激发态能量和自旋轨道耦合效应所引起的13C第一激发态的能级劈裂,并对Λ-12C、Λ-16O等效相互作用位和13C、17O的有关问题进行了分析和讨论. 相似文献
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The 13C(6Li, t)16O reaction has been studied at 34 MeV. Selective population of narrow states is observed up to 21 MeV excitation in 16O. This reaction populates strongly both unnatural-and natural-parity states that have little or no 12C + α0 width. The measured angular distributions are compared with Hauser-Feshbach and finite-range DWBA calculations. Reasonable agreement with the DWBA calculations is found for most of the states strongly populated. The widths of the narrow states populated in the 16–20 MeV excitation region are presented. Comparison of the present data with that from medium-energy inelastic scattering and other multiparticle transfer reactions is made. 相似文献
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T. Tanabe M. Yasue K. Sato K. Ogino Y. Kadota Y. Taniguchi K. Makino M. Tochi 《Physics letters. [Part B]》1981,100(3):241-244
The angular distributions of the reaction 16O(6Li, d)20Ne at 75 MeV for transitions to members of the ground state band are well fitted by exact finite-range DWBA calculations assuming a direct α-cluster transfer and yield spectroscopic factors in good agreement with shell-model predictions. 相似文献
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Four-particle-transfer processes induced by the (6Li, d) and (16O, 12C) reactions to strongly excited 0+ states are compared. Although the selectivity displayed by these reactions is similar, the corresponding relative cross sections are rather different. These results emerge naturally from a simple microscopic model. 相似文献
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N. Anantaraman H.E. Gove R.A. Lindgren J. Tōke J.P. Trentelman J.P. Draayer F.C. Jundt G. Guillaume 《Nuclear Physics A》1979,313(3):445-466
The 16O(6Li, d)20Ne reaction has been studied at bombarding energies of 20, 32 and 38 MeV. The α-particle spectroscopic strengths have been extracted for levels up to 12.15 MeV in excitation. Nondirect processes appear to contribute significantly to all levels at 20 MeV and to high spin levels (6+ and 8+) at 32 MeV. Strengths extracted for members of the ground state band assuming (sd)4 transfer are unequal at both 32 and 38 MeV, in marked contrast to theoretical predictions. To explain this, particle-hole correlations in 16O(g.s.), inelastic channel coupling in the reaction and perhaps other effects as well, have to be considered. Strengths extracted for members of excited bands and α-decay reduced widths compare poorly with each other and with simple SU(3) predictions. 相似文献
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N. Anantaraman H.E. Gove J.P. Trentelman J.P. Draayer F.C. Jundt 《Nuclear Physics A》1977,276(1):119-129
Results from a study of the 18O(6Li, d)22Ne reaction at a 6Li energy of 32 MeV are reported. The L-dependence of the shapes of the measured angular distributions provide a check on recent Jπ assignments for some of the high-lying levels in 22Ne. A finite range distorted wave analysis assuming a direct cluster transfer has been used to extract from the data α-particle spectroscopic strengths for most of the natural parity levels populated below 8 MeV of excitation. These strengths are compared with theoretical predictions for those few states for which a definite correspondence can be made between the calculated and experimental levels of 22Ne. For transitions to the members of the ground-state band, the observed strengths disagree with the predictions. This disagreement has also been observed in the 16O(6Li, d) reaction and its cause is not understood. It is in marked contrast with the good agreement found for (6Li, d) reactions on targets of mass 20 ≦ A ≦ 24. 相似文献
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The transfer reactions 28Si(16O, α)40Ca and 16O(16O, α)28Si have been studied within the framework of the two-channel generator coordinate method. The geometry of the reactions has been discussed in terms of the cross-channel overlap kernels of the generating functions. A clear connection between maxima in the reaction rate and entrance channel resonances has been established. A two-step reaction mechanism involving quasimolecular resonances of inelastic 16O-16O channels is discussed as a possible explanation for narrow structures seen in the 16O(16O, α)28Si reaction cross section. 相似文献
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M. Wery 《Nuclear Physics A》1973,210(2):329-340
Angular distributions and excitation functions have been measured for the 16O(t, t) reaction from 1.4 to 3.7 MeV triton energy using a differentially pumped gas target. The observed resonances have been analysed with the Humblet-Rosenfeld theory. It appears that the 13–15 MeV excitation range of the compound system of 19F is dominated by several levels of large triton partial width. Levels populated in the three-particle transfer reaction (7Li, α) on 16O are compared with the resonances. 相似文献
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G.D. Gunn R.N. Boyd N. Anantaraman D. Shapira J. Toke H.E. Gove 《Nuclear Physics A》1977,275(2):524-532
The 16O(6Li, d)20Ne reaction to the 2?, 4.97 MeV, 3?, 5.63 MeV, and 4?, 7.01 MeV members of the Kπ = 2? band has been studied. Angular distributions were measured at 32 MeV from 7.5° to 145° (lab). Excitation functions were measured at 15° (lab) and 145° (lab) from 31 to 33 MeV and 31.75 to 32.5 MeV, respectively. Results of multi-step and compound nuclear calculations are compared to the data. At this incident energy, both mechanisms appear to contribute to the population of the unnatural parity levels. 相似文献
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L.J.B. Goldfarb 《Physics letters. [Part B]》1982,115(3):166-170
The effects of sequential transfer of a pair of neutrons in the reactions 18O(p, t)16O, 48Ca(t, p)50Ca and 90Zr(t, p)92Zr are found to be sizeable. Channel spin-orbit distortion is an important feature of the calculations of the 18O and the 48Ca reactions. 相似文献
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Coupled-channels study of projectile and target excitation in the scattering of 6Li from 12C and 16O
J. Cook 《Nuclear Physics A》1985,445(2):350-366
Coupled-channels calculations are presented tor elastic and inelastic 6Li + 12C scattering at Ec.m. = 16 MeV and 20 MeV, and for 6Li + 16O at 18.7 MeV. Excitation of states within 6Li, 12C and 16O are treated with rotational, rotation-vibration and vibrational models only. The 3+6Li and 2+12C states are strongly coupled to the elastic scattering and reduce the strengths of both the real and imaginary potentials. The 3?16O state reduces only the strength of the imaginary potential. All other states are weakly coupled and have little effect on each other or the potential. The data are reasonably well described, with there being some preference for the 3? state in 12C to be K = 0. Excitation of the 02+ state in 12C requires a combination of β-vibration and monopole breathing-mode form factors. The deformation lengths found are in poor agreement with those deduced from electron or proton scattering. 相似文献