Zero-field electron transport and energy relaxation in noble gases and SF₆/buffer gas mixtures

The time evolution of the zero-field distribution functions and transport parameters of electrons injected into some atomic and (electronegative or non-electronegative) molecular gases are calculated. The method used is based on a numerical solution of a time-dependent Boltzmann equation written for the case of infinite space. The accuracy of this method is checked initially on model gases. The relaxation time in the short time scale is then obtained for noble gases (Ar, Xe, Ne and Kr) and compared to some data available in the literature. Finally, the authors show that the distribution function in SF 6 /buffer gas mixtures is not Maxwellian as usually assumed.