Electron-ion recombination rate constants in dense gaseous argon and krypton: Effects of electric field strength and the addition of N-2 or CH4

The electron mobilities, mu (e), and electron-ion recombination rate consta nts, k(r), in dense gaseous Ar and Kr with a small amount of N-2 or CH4 as a molecular impurity have been measured as a function of electric field str ength using a pulse radiolysis dc-conductivity method combined with a new d ecay-curve analysis method in which a space-charge effect is taken into acc ount to obtain more accurate values of k(r). The energy of electrons in rec ombination is controlled experimentally in two ways; one is heating-up by t he electric field and the other is cooling-down by inelastic collisions wit h additive molecules. A large deviation of k(r) from the Debye theory obtai ned in the present experiment has been discussed in terms of the electron m ean free paths and electron energies based on recent theories. (C) 2001 Ame rican Institute of Physics.