ANISOTROPIC LOW-ENERGY ELECTRON COLLISION CROSS-SECTIONS FOR METHANE DERIVED FROM TRANSPORT-COEFFICIENTS

Based on a comprehensive set of transport parameters of electrons in methane derived from single electron spectra in the range of field 0.01-15 Td we determined a set of elastic and inelastic scattering cross sections up to 3 eV. The necessity to include anisotropic elastic scattering in a Boltzmann analysis of methane is demonstrated. In addition the drift velocity in a mixture of methane with helium was used to enhance the reliability of the derived cross sections. The low energy part of the cross sections for elastic scattering is subject to a MERT analysis and is compared with total cross section data from single scattering experiments.