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The nuclear shell model is partly analogous to the atomic shell model, which describes the arrangement of electrons in an atom, in that a filled shell results in better stability. When adding nucleons ( protons and neutrons ) to a nucleus, there are certain points where the binding energy of the next nucleon is significantly less than the last one.
The Nilsson model is a nuclear shell model treating the atomic nucleus as a deformed sphere. In 1953, the first experimental examples were found of rotational bands in nuclei, with their energy levels following the same J(J+1) pattern of energies as in rotating molecules.
The liquid drop model is one of the first models of nuclear structure, proposed by Carl Friedrich von Weizsäcker in 1935. [5] It describes the nucleus as a semiclassical fluid made up of neutrons and protons, with an internal repulsive electrostatic force proportional to the number of protons.
The adoption of the term "nucleus" to atomic theory, however, was not immediate. In 1916, for example, Gilbert N. Lewis stated, in his famous article The Atom and the Molecule, that "the atom is composed of the kernel and an outer atom or shell." [12] Similarly, the term kern meaning kernel is used for nucleus in German and Dutch.
In the shell model for the nucleus, magic numbers are the numbers of nucleons at which a shell is filled. For instance, the magic number 8 occurs when the 1s 1/2 , 1p 3/2 , 1p 1/2 energy levels are filled, as there is a large energy gap between the 1p 1/2 and the next highest 1d 5/2 energy levels.
Shell model can mean: Nuclear shell model, how protons and neutrons are arranged in an atom nucleus; Electron shell, how electrons are arranged in an atom or molecule; SHELL model, a model of human factors in aviation
[40] [50] The later nuclear shell model suggested that nuclei with about 300 nucleons would form an island of stability in which nuclei will be more resistant to spontaneous fission and will primarily undergo alpha decay with longer half-lives.
The orbits with the highest angular momentum are "circular orbits" outside the inner electrons, but orbits with low angular momentum (s- and p-subshell) have high subshell eccentricity, so that they get closer to the nucleus and feel on average a less strongly screened nuclear charge. Wolfgang Pauli's model of the atom, including the effects of ...