α decay preformation probabilities across the N = 126 shell closure based on the single particle energy spectra
α decay preformation probabilities across the N = 126 shell closure based on the single particle energy spectra
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DOI：
10.1088/1361-6471/aac981
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发表时间：
2018-06
期刊：
影响因子：
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通讯作者：
Xiaodong Sun;Hong-Fei Zhang
中科院分区：
文献类型：
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作者：
Xiaodong Sun;Hong-Fei Zhang
在相对论Hartree-Bogoliubov模型下，根据单粒子能谱，定义微观价核子数和空穴数，提出了一种计算α衰变预成几率的简明方法.剩余相互作用包括中子-中子、质子-质子配对和质子-中子关联，在平均场假设下，伴随沿着独立的粒子运动，可以触发价核子和空穴的集体运动.因此，价核子和空穴的数目越多，α粒子成团等集体运动就越强。我们假设价轨道位于费米面附近，服从Fermi-Dirac分布，即占据远离费米面能量低（高）得多的轨道的核子（空穴）不能被认为是价核子（空穴）。在N p N n方案下，根据价质子-中子相互作用计算了α衰变预成几率P α。作为一个例子，对于偶偶钋、氡、镭和钍同位素，在广义液滴模型中得到的α衰变预成几率，在N = 126壳层闭合时，考虑壳层效应，可以用两个不同的公式很好地再现。
We put forward a concise approach to calculate the α decay preformation probabilities by defining the microscopic valence nucleon and hole numbers based on the single particle energy spectra, which is obtained within the relativistic Hartree–Bogoliubov model. The residual interactions including neutron–neutron, proton–proton pairing and proton–neutron correlations could trigger the collective motions among the valence nucleons and holes, along with the independent particle motions under the mean field assumption. Therefore the more the number of valence nucleons and holes, the stronger the collective motions such as α particle clustering. We assume that the valence orbits locate around the Fermi surface obeying a Fermi–Dirac distribution, i.e. nucleons (holes) occupying the orbits with much lower (higher) energies away from the Fermi surface can not be considered as the valence nucleons (holes). The α decay preformation probabilities P α are calculated within the N p N n scheme in terms of the valence proton–neutron interaction. As an example, in the case of even–even polonium, radon, radium and thorium isotopes the extracted α decay preformation probabilities , which are obtained within the generalized liquid drop model, can be well reproduced by employing two different formulas to take into account the shell effect at N = 126 shell closure.