Drift Velocities of Slow Electrons in Methane, Ethane, Ethylene, Propylene, Acetylene, and 1-Butene

摘要

A double-shutter drift tube was used to measure the drift velocities of electrons in methane, ethane, ethylene, acetylene, propylene, 1-butene, and ethane-acetylene mixtures for low E/P values. The resulting data were analyzed to obtain values of momentum-transfer cross sections as a function of electron energy in the interval 0.01-0.063 ev. Cross sections for the individual gases were obtained by fitting power series in electron velocity to the slope of the drift velocity curves in the thermal equilibrium range, where the electron velocities can be represented by a Maxwellian distribution. Momentum-transfer cross sections for the dipolar gases--propylene and 1-butene--are compared with Altschuler's dipole scattering theory. (Author)