Nuclear structure and stability

As with electrons in atoms, it is necessary to use the quantum theory to account for the details of nuclear structure and stability. It is favorable to pair nucleons so that nuclei with even numbers of either protons or neutrons (or both) are generally more stable than ones with odd numbers. The shell model of nuclei, analogous to the orbital picture of atoms (see Topics A2 and A3) also predicts certain magic numbers of protons or neutrons, which give extra stability. These are... 

Keywords Relativistic stars - structure and stability, Quark-gluon plasma, Nuclear physics... 

Nuclear synthesis is similar in some ways to inorganic or organic chemical syntheses with the synthetic chemist or physicist having to understand the reactions involved and the structure and stability of the intermediate species. While, in principle, the outcome of any synthesis reaction is calculable in practice such calculations are, for the most part, very difficult. Instead, the cleverness of the scientists involved, their manipulative skills, and the instrumentation available for their use often determine the success of many synthetic efforts. 

It can now be predicted with confidence that machine calculations will lead gradually toward a really fundamental quantitative understanding of the rules of valence and the exceptions to these toward a real understanding of the dimensions and detailed structures, force constants, dipole moments, ionization potentitils, and other properties of stable molecules and equally unstable radicals, anions, and cations, and chemical reaction intermediates toward a basic understanding of activated states in chemical reactions, and of triplet and other excited states which are important in combustion and explosion processes and in photochemistry and in radiation chemistry and also of intermolecular forces further, of the structure and stability of metals and other solids of those parts of molecular wave functions which are important in nuclear magnetic resonance, nuclear quadrupole coupling, and other interaction involving electrons and nuclei and of very many other aspects of the structure of matter which are now understood only qualitatively or semi-empirically. 

Fermi irradiated uranium with slow neutrons, and observed a variety of radioactivities that he tentatively identified as being transuranium elements [1]. We now know that these radioactive species were the products of the fission of the in the sample. Study of the chemical properties of these new nuclides led to the subsequent discovery of fission in 1939 [2, 3], Explanation of the fission process was closely connected to the creation of the liquid-drop model [4—6], in which the nucleus is treated like an incompressible charged fluid with surface tension. See Nuclear Structure of Superheavy Elements for more information on nuclear structure and the stability of the heaviest nuclides. 

In order to co clarify the role of complex formation, the new data on stability constants should be accumulated, being collected at strictly similar conditions. It should be also mentioned that any analysis of equilibrium in solutions involving anions of polybasic hydroxy carboxylic acids requires the data on the deprotonation constants of the acid in question. This information would be crucial for conclusions regarding the presence and stability of mixed complexes in the system. Valuable knowledge about the structure of complex compounds present in solutions (and in precursors as well, see later) may be gained by means of vibrational spectroscopy (IR and Raman spectra) and nuclear magnetic resonance. 

In should be noted that both Harkins and Rutherford were interested in the details of nuclear structure from the point of view of understanding stability of nuclei and understanding which mass numbers are stable. This is an important study but it is really nuclear physics and is beyond the scope of this book. 

As a consequence, by breaking up a heavy nucleus (fission) to produce lighter and more stable nuclei, energy is once again released. Detailed examination of the stability curve reveals other important features of nuclear structure which are strongly correlated with observed abundances. 

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