Electron impact ionization section plot

Figure 6.1 Electron impact ionization cross sections (in square centimeter) for the /f-shell in C are plotted as a function of the incident electron energy (in kiloelectron volt). The sources of experimental El ICS data in solid symbols are given in Refs. [66-69]. Solid line (—), dashed...

Figure 1 (a) Single differential cross sections (in the units of 10 cm /eV) as a function of energy loss W (=Ii+s), for the production of cations from electron impact ionization of SiH at constant electron impact energy of 100 eV. (b) Same as (a) but at E=200 eV. (c) The solid lines show the trends of the calculated ratios of cross sections in Platzman plot Y(W) in half energy ran at 100 and 200 eV. 

The PH + ion formed by electron impact on PH3 was mass spectrometrically detected. An ionization efficiency curve between 30 and 50 eV led to appearance potentials of 34.0 eV (square root plot) or 32.7 eV (linear extrapolation) [1] both values are tabulated in [2] for the first value, see also [3]. Partial PH3 ionization cross sections for PH + and PD3 ionization cross section ratios, PDl /PD, were obtained for electron energies up to 180 eV and showed appearance potentials of 35.0 0.5 eV for PH + and 34.9 0.5 eV for PD + (square root plots) [4]. The PH + ion was also mass spectrometrically detected after ionization of PH3 by high-energy electrons (8 keV). Oscillator strengths were obtained by dipole (e,e+ion) spectroscopy simulating photoionization [5]. 

Fig. 5.9. Scaled cross section for K-shell ionization by electron impact for various light targets plotted as a scaled function of the projectile energy. The dotted line is the PWBA result, and the broken line is the PWBA-Ochkur exchange result. , is incident projectile energy and I the binding energy of die target atom. The graph is from Hippier [5.20] where details for the data can be found.

Any technique for gas analysis can be applied to EGA. The most frequently used methods are mass spectroscopy (MS) and Fourier transform infrared spectroscopy (FTIR). Many instrument manufacturers provide the ability to interface their TGAs with MS or FTIR (see Section 3.7, on instrumentation). Temporal resolution between the TGA and the MS or FTIR detector is an important feature, for example, in distinguishing absorbed water from water as a reaction product and in assigning a decomposition product to a specific mass loss. Each method has its experimental requirements, limitations, and advantages. Mass spectroscopy is a very sensitive technique that identifies volatile species by their mass-to-charge ratio, referred to as m/z. The evolution of the sum of all mJz species can be plotted and compared with the derivative TGA plot to ensure temporal resolution between the TGA and the mass spectrometer. The evolution of a specific mJz, associated with species such as water or formaldehyde, can show the distinct evolution of these compounds. The most common ionization is by 70eV electron impact (El), which operates... 

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