Total and ionization cross sections of electron scattering by fluorocarbons

Antony, Bobby; Joshipura, K. N.; Mason, Nigel J.

doi:10.1088/0953-4075/38/3/005

Cited by 43 publications

(34 citation statements)

References 56 publications

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“…The BEB cross sections are generally significantly larger (and their maxima are shifted to higher electron impact energies) than the DM cross sections -ranging from a factor of 1.7 in case of Fe 2 O 2 down to 1.4 in case of Fe 3 O 4 -which is in line with a study on iron hydrogen clusters EICSs [22] in which also discrepancies between those two methods were obtained which were larger than previously assumed to be the norm. We note that there have been cases reported in which the DM method resulted in cross sections which were significantly smaller and also showed a faster decrease beyond the maximum than it was the case for cross sections obtained using other methods or experimental ones [66][67][68]. In reference [22] the discrepancy between DM and BEB cross sections was related to the different methodological foundations of the methods, and especially to the explicit inclusion of geometric parameters in terms of the radius of maximum radial density of atomic subshells (see also Sect.…”

Section: Electron Impact Ionisation Cross Sectionsmentioning

confidence: 55%

Electron impact ionisation cross sections of iron oxides

et al. 2017

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Abstract. We report electron impact ionisation cross sections (EICSs) of iron oxide molecules, FexOx and FexOx+1 with x = 1, 2, 3, from the ionisation threshold to 10 keV, obtained with the Deutsch-Märk (DM) and binary-encounter-Bethe (BEB) methods. The maxima of the EICSs range from 3.10 to 9.96 × 10 −16 cm 2 located at 59-72 eV and 5.06 to 14.32 × 10 −16 cm 2 located at 85-108 eV for the DM and BEB approaches, respectively. The orbital and kinetic energies required for the BEB method are obtained by employing effective core potentials for the inner core electrons in the quantum chemical calculations. The BEB cross sections are 1.4-1.7 times larger than the DM cross sections which can be related to the decreasing population of the Fe 4s orbitals upon addition of oxygen atoms, together with the different methodological foundations of the two methods. Both the DM and BEB cross sections can be fitted excellently to a simple analytical expression used in modelling and simulation codes employed in the framework of nuclear fusion research.

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Section: Electron Impact Ionisation Cross Sectionsmentioning

confidence: 55%

Electron impact ionisation cross sections of iron oxides

et al. 2017

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“…At elevated CF 4 partial pressures the secondary electron yield is also affected by the different ionization potentials of Ar and CF 4 (I Ar = 15.76 eV, I CF4 = 16.91 eV [35]). For ion energies below 1 keV, which is the case for the here applied processes, γ SE is entirely depending on the target material and the sputter gas.…”

Section: Synthesis Of Cf X Thin Filmsmentioning

confidence: 99%

“…Moreover, since the ionization potentials from fractured CF 4 species are considerably lower (I CF = 9.11 eV, I CF2 = 11.44 eV and I CF3 = 8.9 eV [35]) than for CF 4 it is reasonable to assume an increased importance of those ionized radicals contributing to the plasma chemistry.…”

Section: Synthesis Of Cf X Thin Filmsmentioning

confidence: 99%

CFx thin solid films deposited by high power impulse magnetron sputtering: Synthesis and characterization

Schmidt

Greczyński

Goyenola

et al. 2011

Surface and Coatings Technology

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atmosphere. The fluorine content of the films was controlled by varying the CF 4 partial pressure from 0 mPa to 110 mPa at a constant deposition pressure of 400 mPa and a substrate temperature of 110 ºC. The films were characterized regarding their composition, chemical bonding and microstructure as well as mechanical properties by applying elastic recoil detection analysis, Xray photoelectron spectroscopy, Raman spectroscopy, transmission electron microscopy, and nanoindentation. First-principles calculations were carried out to predict and explain Fcontaining carbon thin film synthesis and properties. By geometry optimizations and cohesive energy calculations the relative stability of precursor species including C 2 , F 2 and radicals, resulting from dissociation of CF 4 , were established. Furthermore, structural defects, arising from the incorporation of F atoms in a graphene-like network, were evaluated. All as-deposited CF x films are amorphous. Results from X-ray photoelectron spectroscopy and Raman spectroscopy indicate a graphitic nature of CF x films with x ≤ 0.23 and a polymeric structure for films with x  0.26. Nanoindentation reveals hardnesses between ~1 GPa and ~16 GPa and an elastic recovery of up to 98 %.

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“…Though this method can attain good results over a wide energy range, the applications are limited since the two adjustable values are different for each target, and their value determinations require experimental findings. Recently, to find the TCSs of electron scattering by molecules, Antony et al (2005) have also proposed a modified AR named the group additivity method, where the cross section arising from each constituent group of a molecule was added together to obtain the molecular TCS. Using this method, they have computed the TCSs of electron scattering by several molecules.…”

Section: Introductionmentioning

confidence: 99%