Electron kinetic energy through

Figure 3. Electron mean free path as a function of electron kinetic energy through organic materials. Key V, PMMA , poly(p-xylene) O, plasma polymerized fluorocarbon , barium stearate 0, cadmium arachidate and A, carbon. (Reproduced, with permission from Ref. 35.)...

The chief content of the isomorphism displayed in Table 1 is embodied in the phrase "electride ion . By introducing at the outset in the electronic interpretation of chemistry the wave-like character of electrons and the Exclusion Principle through the concept of van der Waals-like electron-domains or electride ions , whose sizes indicate the magnitudes of the electrons kinetic energies, whose impenetrability8) simulates, at least approximately, the operation of the Exclusion Principle, and whose charges yield within the framework of the model easily foreseeable effects, one transforms the complex treatment of the covalent bond in quantum mechanics into a simpler, if less precise, exercise in classical electrostatics. 

In closing this section, we note that although the Koopmans picture is a simplification of the ionization dynamics, it provides a very useful zeroth order picture from which to consider the TRPES results. Any potential failure of this independent electron picture can always be experimentally tested directly through variation of the photoionization laser frequency resonance structures should lead to variations in the form of the spectra with electron kinetic energy, although the effect of resonances is more likely to be prominent in PAD measurements, and indeed an observation of a shape resonance in p-difluorobenzene has been reported [153, 154]. 

In a conventional PE apparatus the spectrum is obtained by scanning the electron kinetic energy at a fixed wavelength of photons. Most frequently applied photon sources are Hel and Hell radiation produced by low-pressure discharge through helium. 

A eharged particle moving through a certain material loses its kinetic energy through interactions with the electrons and nuclei of the material. Eventually, the particle will stop, pick up the necessary number of electrons from the surrounding matter, and become neutral. For example,... 

As recoils pass through matter, they lose kinetic energy through electronic excitation and ionization. Only when they have slowed to about 1 keV or less do they begin to form stable molecular bonds. At this point, the most probable charge state is, in general, either - -l or 0. Accordingly, we have included a brief discussion of the chemical fate of... 

---