Elastic electron scattering by the CF₃radical in the 1–1000 eV energy range

Abstract

Elastic scattering of electrons by CF 3 radical has been studied theoretically in a wide energy range of 1-1000 eV in the framework of independent-atom model (IAM). The optical potential method is used for calculating the electron scattering amplitudes of the different atoms of the target molecule. The differential and integral cross sections are calculated for equilibrium internuclear distances of the ground state of the CF 3 radical in two approaches -IAM and additivity rule (IAM-AR) approximations. The calculated cross sections are compared with the experimental data for e + CF 3 and e + CF 3 H scattering and with other theoretical results. It is justified that the IAM performs slightly better for the differential cross sections, while the simpler IAM-AR approximation describes the integral cross sections better.

Elastic electron scattering by halocarbon radicals in the independent atom model approach

“…where r ij = r i − r j are the internuclear distances. The OP method is used to study the behaviour of the differential as well as the integral elastic and momentum transfer cross sections of electron scattering by molecules [23][24][25][26]. In the IAM framework the DCS of elastic electron scattering by an N -atomic molecule, after averaging over the random vibrational and rotational degrees of freedom of the molecule, could be expressed as follows [6,16,17] (atomic units = e = m e = 1 are used throughout the work, unless otherwise noted):…”

“…Based on our previous experience [24][25][26], we suppose that the scattering cross sections for the whole molecule can be described well, when using a sufficiently good theoretical description of scattering by the particular atoms of the molecule, so not only in case of fast incident electrons, when k(r nm ) min 1, but also at lower energies, in case of k(r nm ) min > 1.…”

“…For low collision energies, up to 10 eV the main contribution in the calculated ICSs is originated from the cross sections of e − + C collision, while above 10 eV -from the e − + F scattering (see the cross section analysis in [26]). The significant overestimation of our calculated cross sections compared to the experimental ones is due to the fact that the contribution of the carbon atom is substantially smaller than the contribution of the fluorine atoms at this energy.…”

“…e − + CF 2 and e − + CF 3 . In Figure 1b our cross sections are compared with the available experimental data for e − + CF 3 [2,3] and e − + CF 2 [43] processes (see also [26,44,45]). It is worth noting that the experimental data were obtained with a rather high uncertainty (see Fig.…”

“…However, as one can see in Figure 1b, as the number of fluorine atoms in the radicals is decreasing, the amplitudes of the experimental and calculated cross sections are also decreasing. Therefore, in case of e − + CF 2 scattering the calculated cross sections are mainly determined by the contribution of the C atom up to ∼35 eV collision energies, while above this -by the contribution of the fluorine atoms (see the e − + C and e − + F cross sections in [26]). The overestimation of the calculated cross sections over the experimental ones up to this energy allows one to conclude that the contribution of the carbon atom is again smaller compared to the contribution of the fluorine atoms.…”