Comparison of Electron Diffusion Coefficients Defined in Velocity and Position SpacesDVandDTin CF4

Abstract

The transverse diffusion coefficient D T and the conventional expression D V for electrons in CF 4 are compared. The ratio of D V and D T reaches 6 at the maximum. The cause of such large differences between D V and D T are discussed from their definitions and also in relation to the cross sections of CF 4 . When inelastic collisions make the velocity distribution highly anisotropic, D V defined in velocity space is not appropriate to use in place of D T even as an approximate expression.