Shell model

Japanese: 殻模型 - かくもけい

...First, the liquid drop model was proposed, which approximates the atomic nucleus with a liquid drop, due to the saturation property that the nucleon density and binding energy per nucleon of an atomic nucleus are not very dependent on the mass number. This model was successful in explaining the general properties of the atomic nucleus, and it has also become the starting point for models describing the nuclear fission process, the collective motion of atomic nuclei, and more recently, the collisions between heavy atomic nuclei. On the other hand, the shell model, which has been successful in atoms, was introduced by MG Mayer and HD Jensen to explain the stability of atomic nuclei with special numbers of protons or neutrons called magic numbers, and the spin of atomic nuclei. This model, based on the picture of independent particle motion, is not only effective in describing the properties of atomic nuclei near closed shells where both the number of protons and the number of neutrons are magic numbers, but also plays an important role as the basis for the microscopic theory of atomic nuclei based on the degrees of freedom of individual nucleons more generally. ...

From [Nuclear Model]

...If the nucleus is deformed, it is expected to rotate like a top, and in fact, some nuclei are known to have rotational energy levels, and deformed nuclear models are sometimes called rotational (nuclear) models. The independent particle model is based on the premise that there is a mean field within the nucleus, and that nucleons rotate freely within it independently of other nucleons, and the shell model is a representative example. As is well known, electrons within an atom rotate in certain orbits (shells), and when one orbit is full, it forms a closed shell. ...

*Some of the terminology that refers to the "shell model" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…原子核模型としては，まず，原子核の核子密度や核子当りの結合エネルギーが質量数にあまり依存しないという飽和性から，原子核を液滴で近似する液滴模型が提唱され，この模型は原子核のおおまかな性質を説明するのに成功すると同時に，核分裂過程，原子核の集団運動，さらには最近の重い原子核どうしの衝突などを記述する模型の出発点となっている。一方，陽子数または中性子数が魔法数と呼ばれる特別の数となる原子核は安定であることや原子核のスピンを説明するために，原子で成功した殻模型がM.G.メイヤー，H.D.イェンゼンによって導入された。独立粒子運動の描像に基づくこの模型は，陽子数，中性子数ともに魔法数であるような閉殻の近くの原子核の性質を記述するのに有効であるばかりでなく，より一般に個々の核子の自由度に基づく原子核の微視的理論の基礎として重要な役割を演じている。…

【原子核模型】より

…また原子核が変形すればこまのような回転が予想されるが，事実ある原子核は回転エネルギー準位をもつことが知られており，変形核模型を回転(核)模型ということがある。　独立粒子模型は，核内には平均場があって，核子はその中を他の核子とは独立に自由に回転するという立場に立つもので，殻模型(シェルモデル)が代表的なものである。よく知られているように，原子内の電子は一定の軌道(殻)を回転し，一つの軌道が満員になると閉殻をつくる。…

※「殻模型」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典第２版について | 情報

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