A measurement of drift velocity and longitudinal diffusion coefficient of electrons in pure carbon dioxide

Recently we determined a set of electron collision cross sections for carbon dioxide molecule by analyzing electron swarm data measured in dilute CO2-Ar mixtures. This cross section set predicts existence of a prominent peak in the longitudinal diffusion coefficient of electrons in pure CO2 gas, which has not been observed experimentally. In the present study, we have measured the drift velocity W and the gas number density times the longitudinal diffusion coefficient, NDL, of electrons in pure carbon dioxide gas over the E/N range 0.25-100 Td and confirmed the existence of a peak in the NDL as our cross section set predicts. This fact indicates the correctness of the magnitude of the resonance peak for the vibrational excitation cross section determined in our swarm study using CO2-Ar mixtures