Electronic shell model

Cl.1.3.1 SIMPLE METAL CLUSTERS AND THE ELECTRON SHELL MODEL... 

Figure Cl. 1.2. (a) Mass spectmm of sodium clusters (Na ), N= 4-75. The inset corresponds to A = 75-100. Note tire more abundant clusters at A = 8, 20, 40, 58, and 92. (b) Calculated relative electronic stability, A(A + 1) - A(A0 versus N using tire spherical electron shell model. The closed shell orbitals are labelled, which correspond to tire more abundant clusters observed in tire mass spectmm. Knight W D, Clemenger K, de Heer W A, Saunders W A, Chou M Y and Cohen ML 1984 Phys. Rev. Lett. 52 2141, figure 1.

The spherical shell model can only account for tire major shell closings. For open shell clusters, ellipsoidal distortions occur [47], leading to subshell closings which account for the fine stmctures in figure C1.1.2(a ). The electron shell model is one of tire most successful models emerging from cluster physics. The electron shell effects are observed in many physical properties of tire simple metal clusters, including tlieir ionization potentials, electron affinities, polarizabilities and collective excitations [34]. 

G. Metal Cluster and Metal Oxide Anion Reactions Cluster Reactivities Reactivities and the Electronic Shell Model... 

However, the hquid drop model is powerless to explain the more detailed features within the binding energy per nucleon curve, such as the various discontinuities that are superimposed on it, reflecting the enhanced stabihties of nuclei of He, C, 0, Ne, and Mg. To explain these more subtle features, we need to consider the quantum mechanical nuclear-sheU model, which bears a number of similarities to the electron-shell model as described in chapters 7 and 9. 

Certain numbers of protons and neutrons appear to be particularly stable 2,8,20,28, 50, 82, and 126. These magic numbers were first suggested by Maria Mayer (1906-1972), who developed a nuclear shell model similar to, but much less regular than, the electron shell model discussed in Chapter 6. For her work, Maria Mayer won the Nobel Prize in Physics in 1963. The Nobel Prize in Physics has been awarded yearly (except between 1940 and 1942) for 106 years, and the only women to have won this prize so far are Maria Mayer and Marie Curie. 

---