Electron swarm parameters in pure C_2H_2 and in C _2H_2-Ar mixtures and Electron collision cross sections for the C_2H_2 molecule

摘要

Electron swarm parameters (the drift velocity and the longitudinal diffusion coefficient) were measured in pure C_2H_2 and also in C2H2-Ar mixtures containing 0.517% and 5.06% acetylene over wide E/N ranges. These swarm parameters were analysed using a Boltzmann equation analysis and a set of electron collision cross sections for the C_2H_2 molecule was derived so that it was consistent with the present swarm data and published ionization coefficient. The present result suggested the presence of a Ramsauer-Townsend minimum in the elastic momentum transfer cross section at 0.08 eV and prominent threshold and resonance peaks in the υ4/υ5 vibrational excitation cross section. The present cross section set was also confirmed to be consistent with the published experimental total cross section of C_2H_2.