Elastic electron scattering by the CF2Cl and CFmolecules in the potential approach


Purpose. Studying the electron scattering by fluorocarbon CFn and chlorofluorocarbon CFnCl4-n (n = 1–4) molecules is of high importance in plasma (gas-discharge, low-temperature and industrial), gaseous laser and semiconductor processing technologies, as well as in atmospheric sciences and ecology. The cross sections of these processes are very important for modelling the mechanisms in low-temperature plasma. Such plasma processes are widely used in industry.
Methods. The independent atom model approach with the optical potential method are used to study the elastic scattering of electrons by CF3, CF2Cl and CF2 molecules The scattering cross section are calculated in two approximation of this model – the IAM approach is used for the differential, while the IAM-AR is used for the integral cross sections. The amplitudes of electron scattering by the carbon, fluorine and chlorine atoms of the target molecules are obtained from the corresponding phase shifts, using the parameter-free real and complex optical potentials.
Results. The integral and differential cross sections are calculated at the ground-state equilibrium geometry of the target molecules and compared with the available experimental data. The differential cross sections are analysed at 10, 15, 20, 25, 40 and 50 eV collision energies. The elastic integral cross sections are obtained in the 1–100 eV energy range, while the momentum transfer cross sections are calculated from 1 eV up to 1000 eV.
Conclusions. The comparison of the cross sections for the CF2Cl and CF3 target molecules shows a rather strong dependence on the chlorine atom, which increases the amplitude and the angular behaviour of the cross section. Our cross sections are in a rather good qualitative agreement with the measured ones above 10–20 eV energies, depending on the target type

Keywords: scattering, amplitude, differential cross section, integral cross section, optical theorem, optical potential