Knudsen diffusion is a phenomenon whereby transport takes place by gas–pore wall collisions rather than by gas–gas collisions

Knudsen diffusion is a phenomenon whereby transport takes place by gas–pore wall collisions rather than by gas–gas collisions. Knudsen diffusion is modeled using concepts similar to the kinetic theory of gases as DKA = (dp/3)c¯, where c¯ means the molecular velocity given earlier in Eq. (1.37). Use this to derive the following equation for the Knudsen diffusion coefficient:

DKA = 4850dp  T MA (9.61) Calculate the value for silane diffusing in 10-μm-diameter pores at 900 K, which is representative of the deposition of solid silicon in thin tubes.