THE REFLECTION OF METASTABLE PARTICLES AT A SURFACE

At low pressures, diffusion plays an important role in determining the number density n(r) of metastable particles created in an electrical discharge. The appropriate surface boundary condition for solving the metastable diffusion equation is known to be of the form n(r) is-propo rtional-to s . deln, where s is the unit vector normal to the surface. In this paper a new expression for the proportionality constant is de rived using the arguments of gas kinetics. This expression is used to estimate the reflectivities of a variety of types of metastable partic le.