Inner-shell ionization

In addition, inner-shell ionization contributes to the intensity of the z line. The removal of an inner-shell electron leads directly to the ls2s excited level of the He-like system. The contribution of this process is proportional to the concentration of the Li-like ions and should be taken into account at low electron temperatures or if the charge state distribution differs from ionization equilibrium. 

The ratio between the w-line, which is predominantly excited by electron collisions (8.1), and the k-satellite, which is populated by dielectronic recombination (8.2), depends on the electron temperature only. The ratio between the w line and the intensity of the collisional excited Li-like satellites (8.5), depends on the density ratio between the Li-like and He-like ions, as the collisional excitation rates for the allowed transitions in the He-like system and in the doubly excited Li-like system are similar. 

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Used effects Phonon excitation (20 meV-1 eV) Plasmon and interband excitations (1-50 eV) Inner-shell ionization (A = ionization energy loss) Emission of x-ray (continuous/characteristic, analytical EM)... 

A consequence of absorption of X rays is the inner shell ionization of the absorbing atoms and the subsequent generation of characteristic X rays from the absorbing atoms, called secondary fluorescence, which raises the generated intensity over that produced by the direct action of the beam electrons. Secondary fluorescence can be induced by both characteristic and bremsstrahlung X rays. Both effects are compo-sitionally dependent. 

A particular strength of Equation (7) is that the intensity ratio is formed between mea-surements of the same X-ray energy in both the unknown and standard. This procedure has significant advant es First, there is no need to know the spectrometer s efficiency, a value that is very difficult to calibrate absolutely, since it appears as a multiplicative factor in both terms and therefore cancels. Second, an exact knowledge of the inner shell ionization cross section or fluorescence yields is not needed, since they also cancel in the ratio. 

The inner-shell ionization energies are eolleeted in Table 2 and eompared with the Koopmans estimates (which are seen to be seriously in error) and the best available experimental values. Whilst the Koopmans approximation is clearly incapable of giving good ionization energies and must therefore he used with caution in predicting the chemical shifts in going from one molecule to another, the ionization energies based on (2) are rather satisfactory. 

Individual X-ray photons, 127 Induced birefringence, 89 Inner shell ionization, 123, 124 Inner-orbital ionization, 15 InP, 52... 

Due to the presence of the several electron shells, a series of different X-lay lines are produced in cascades following inner shell ionizations. Notation of the lines corresponds to historical reasons (a is the strongest, P is the next strongest, etc.) and (in case of some minor lines) it is not always logical. The... 

The electron density centered at M is the only central contributor at the nuclear position M, as in this case the nucleus coincides with the field point P, which is excluded from the integrals. For transition metal atoms, the central contributions are the largest contributors to the properties at the nuclear position, which can be compared directly with results from other experimental methods. The electric field gradient at the nucleus, for instance, can be measured very accurately for certain nuclei with nuclear quadrupole resonance and/or Mdssbauer spectroscopic methods, while the electrostatic potential at the nucleus is related to the inner-shell ionization energies of atoms, which are accessible by photoelectron and X-ray spectroscopic methods. 

Stocklin, G. (1979). Chemical and biological effects of (8 -decay and inner shell ionization in biomolecules a new approach to radiation biology, page 382 in Radiation Research, Okada, S., IMAMURA, M., TeRASIMA, T, AND Yamaguchi, H., Eds. (Ibppan Printing Company, Tbkyo). 

Photoelectron O o o Ejection of an electron from the valence or inner shell Ionization energies of valence or inner-shell electrons of molecules (Section 27-5)... 

M. J. Van der Wiel, Progress Report given at Second International Conference on Inner-Shell Ionization Phenomena, Freiburg, March 1976. 

In this section we describe experiments whose aim has been to determine explicitly inner shell ionization cross sections (or ratios of electron and positron cross sections). Section 5.5 contained an account of the influence of inner shell processes on multiple ionization of the heavier noble gases. 

Fig. 5.22. Experimental set-up for studies of positron impact inner shell ionization (Ebel et al, 1989). Key (1) target support (2) lead collimator (3) flange with thin window for the transmission of X-rays to (4) a Si(Li) detector (5) aluminium window 0.1 mm thick (6) Nal(Tl) gamma-ray detector.

Calculations by Gryzinski and Kowalski (1993) for inner shell ionization by positrons also confirmed the general trend. Theirs was essentially a classical formulation based upon the binary-encounter approximation and a so-called atomic free-fall model, the latter representing the internal structure of the atom. The model allowed for the change in kinetic energy experienced by the positrons and electrons during their interactions with the screened field of the nucleus. 

Tobehn, I. (1989). Ratio of inner-shell ionization by low energy electron and positron impact. Phys. Lett. A 140 114-116. 

Gryzinski, M. and Kowalski, M. (1993). Theory of inner shell ionization by... 

Schneider, H., Tobehn, I. and Hippier, R. (1992). Inner-shell ionization by positron and electron impact. Hyperfine Interactions 73 17-26. 

Seif el Nasr, S.A.H., Berenyi, D. and Bibok, Gy. (1974). Positron impact inner shell ionization. Z. Phys. 271 207-210. 

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