Ionization cross sections for plasma relevant molecules

Abstract

We have chosen five complex molecules (C3F6O, C4F8O, C5F10O, C6F12O and C4F7N) for the present investigation, which are considered as potential substitutes for SF6 in plasma applications. There are some theoretical data available for ionization cross sections with contradicting values, especially at the peak. To the best of our knowledge, no experimental data are found in the literature to validate previous calculations. In this work, we have efficiently included nuclear charge distribution and the corresponding electrostatic potential in the spherical complex optical potential formalism for the first time. Thus, the nuclear static effect is included in the calculation of inelastic cross section of these plasma relevant molecules by electron scattering. A complex scattering potential-ionization contribution method is used to derive the ionization cross section. We have done a test run of the adopted changes on targets for which experimental measurements are available. Excellent agreement can be found for the entire energy range. For present plasma relevant molecules, a notable difference is seen in the lower energy region of investigation, which is a major improvement in our calculation. However, beyond the peak, the values are consistent with previous methods. For C6F12O this is the first report of ionization cross section.

Mean Free Paths and Cross Sections for Electron Scattering from Liquid Water

“…The approach is called the spherical complex optical potential (SCOP) method. We have already applied this methodology to several atomic and molecular targets in the past, and it has proved to be reliable in the energy range above the ionization energy (IP) of the target. − The failure of this methodology below the electronic excitation threshold is due to the negligence of rotational and vibrational excitations in the theory, particularly for the polar molecules. This would significantly affect the magnitude of the total inelastic and the total cross sections below about 10 eV.…”

“…For the ionization cross section, the complex scattering potential-ionization contribution (CSP-ic) method is applied. The approach is similar to that applied to gaseous targets.…”

“…Due to the lack of any reliable method for determining the rovibrational effects, these channels are dropped from the present work. For the ionization cross section, the complex scattering potential-ionization contribution (CSP-ic) method 32 is applied. The approach is similar to that applied to gaseous targets.…”

Determination and assessment of a complete and self-consistent electron-neutral collision cross-section set for the C4F7N molecule

“…The dissociative electron attachments to C 4 F 7 N were probed experimentally by Ranković et al in 2020 but the absolute cross-section data were not given [21]. Sinha et al calculated the total inelastic cross-section of C 4 F 7 N using the spherical complex optical potential (SCOP) formalism in 2020 [22]. Based on this, the ionization cross-section and the electronic excitation cross-section were also derived.…”

Brief Review of Electron Collision Studies of Molecules Relevant to Plasma

“…Wang et al [7] have calculated the total Q ion of fluoroketones (C 5 F 10 O and C 6 F 12 O) and fluoronitriles (C 3 F 5 N and C 4 F 7 N) using the BEB method. Sinha et al [69] have calculated the Q ion and electronic excitation cross section for C 3 F 6 O, C 4 F 8 O, C 5 F 10 O, C 6 F 12 O, and C 4 F 7 N using the CSP-ic method from the ionization threshold to 5000 eV. Wang et al [70] have calculated the Q ion for C 5 F 10 O and C 6 F 12 O using the DM method.…”