Auger ionization process

The radicals are produced by various processes, although little is known for certain. A major question exists as to whether the radicals are produced by the initial bond rupture - , by recoil impact , by Auger ionization , by gamma radiation damage or by normal exchange . ... 

The calculations were performed using a double-zeta basis set with addition of a polarization function and lead to the results reported in Table 5. The notation used for each state is of typical hole-particle form, an asterisc being added to an orbital (or shell) containing a hole, a number (1) to one into which an electron is promoted. In the same Table we show also the frequently used Tetter symbolism in which K indicates an inner-shell hole, L a hole in the valence shell, and e represents an excited electron. The more commonly observed ionization processes in the Auger spectra of N2 are of the type K—LL (a normal process, core-hole state <-> double-hole state ) ... 

If the work function is smaller than the ionization potential of metastable state (see. Fig. 5.18b), then the process of resonance ionization becomes impossible and the major way of de-excitation is a direct Auger-deactivation process similar to the Penning Effect ionization a valence electron of metal moves to an unoccupied orbital of the atom ground state, and the excited electron from a higher orbital of the atom is ejected into the gaseous phase. The energy spectrum of secondary electrons is characterized by a marked maximum corresponding to the... 

Fig. 4. Potential energy versus distance from the surface. Data is appropriate for He and tungsten. E, is the ionization potential for helium and ( > is the work function of tungsten. E (e") is the kinetic energy of an emitted secondary electron. The symbol He + nej implies a system composed of an helium ion and n conduction electrons in tungsten. The lower potential curve results from an Auger neutralization process where both electrons were originally at the Fermi level. (The figure is similar to one published in Ref. )...

Let us first consider a simple Auger process with only a single decay channel [Nc = 1, see Eq. (4)]. Although not characteristic of K-shell Auger, such processes take place upon (n - l)p ionization of alkaline earth atoms, for example, in (2p 1) Mg+, where the only nonradiative decay pathway involves the two 3s electrons (2p-1) Mg+ (3s-2) Mg2+ + e. Assume that... 

Auger electron spectroscopy (AES) — When an electron is removed from a level of energy E of a surface atom, the hole is filled by an electron from a higher electronic level E2. The energy difference between the two involved orbitals is transferred to a third electron of level /i3 which then leaves the atom and may be measured as an Auger electron. Due to the mean free path of the electrons AES is a surface analytical method with a depth resolution of some few nm as in the case of XPS. The excitation of electrons and the primary ionization process... 

Below the ionization edge, features in the absorption spectra called discrete resonances are due predominantly to transitions of the core electron to bound states that result from configurations in which the core electron has been promoted to a valence or Rydberg orbital or an appropriate linear combination. These states are degenerate with the ionization continua of other configurations and therefore can autoionize in an Auger-like process where one electron falls into the core hole and another electron is emitted. 

Figure 17.3.9 Schematic view of the Auger emission process from silicon. The atom is ionized initially by an incident electron. That electron and one from the K shell leave the sample as energy loss electrons. The energies of the levels relative to the Fermi level, Ep (Sections 3.6.3 and 18.2), are given on the left. [From C. C. Chang in Characterization of Solid Surfaces, ...

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