Diffusion Coefficient of Electrons in Real Space

A Monte-Carlo simulation of electron motion is carried out by a new method to obtain the exact values of swarm parameters. The elastic and total collision cross sections assumed here are proportional to various powers of the electron energy, and the mass ratio of an electron to a gas atom is taken as 10-2. Computation shows that the well-known expression for the diffusion doefficient D v does not always give the exact values of the lateral diffusion coefficient D T. The differences between the values of D v and D T are significant when the power value of the collision cross-section is large or the mass ratio is large. The disagreement is thought to be caused by the difference in the procedures for obtaining D v and D T because of the difference in their definitions.