The drift velocity and longitudinal diffusion coefficient of electrons in nitrogen and carbon dioxide from 20 to 1000 Td

The distribution of arrival time spectra (ATS) of electrons in nitrogen (N-2) and carbon dioxide (CO2) has been measured over the range of E/N from 20 to 1000 Td (1 Td=10(-17) V cm(2)) at room temperature by a double-shutter drift tube. The drift velocity (W-m) of electrons in N-2 and CO2 was evaluated from these distributions by the ATS method. Moreover, the ratio (D-L/mu) of the longitudinal diffusion coefficient (D-L) to the electron mobility (mu) was measured. The values of W-m and D-L/mu in N-2 and CO2 were in good agreement with experimental and theoretical values obtained by previous investigators except for a few of the earlier studies.