Outer shell ionization, atomic

Due to the high atomic density of solids, it is hard to reach single-collision conditions for processes, such as outer-shell ionization that have cross sections of atomic dimensions. As, furthermore, it would be difficult to detect outer-shell ionization events in a solid, such measurements have until now not been performed. However, for inner-shell ionization, thin foils have the obvious advantage of localization... 

In Auger transitions, incident electrons interact with the inner shell electrons E of the sample. The vacancy created by an ejected inner shell electron is filled by an outer shell electron (Ei), and a second outer shell electron ( 2) is ejected leaving the atom in a doubly ionized state. The electrons ejected from the outer shells are called Auger electrons, named after the Frenchman Pierre Auger, who discovered the effect. Thus, AES measures the energies of the Auger electrons ( a) emitted from the first 10 A of a sample surface. The energy equation is expressed as... 

A) Alkali metals have one electron in their outer shell, which is loosely bound. This gives them the largest atomic radii of the elements in their respective periods. Their low ionization energies result in their metallic properties and high reactivities. An alkali metal can easily lose its valence electron to form the univalent cation. Alkali metals have low electronegativities. They react readily with nonmetals, particularly halogens. 

Outer Shell Element Configuration Atomic Number First Ionization Enthalpy (kJ mol-1) Normal bp (K) A Hvlp (kJ mol"1) % by Volume in the Atmosphere Promotion Energy (kJ mol"1) nship6 — /w2np5(n+l),... 

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