Electron-ion recombination in condensed media

Recent developments in transport-mediated theories of geminate escape probability (φ) and the rate of homogeneous reaction (k) for electron-ion recombination in condensed media are critically reviewed and some new results presented. The escape probability increases with the mean free path, but Monte Carlo calculations indicate much faster rise at large mean free paths compared to analytical calculations based on fractal diffusion. The character of geminate recombination at very large mean free path is questioned. The decrease of k with the mean free path and its increase with an external electric field have been rigorously demonstrated using an integral relationship between k and φ. It is stressed that in comparing with experiments one must be aware of heating effects and of the inefficiency of the final chemical step of the reaction. Certain miscellaneous topics in electron-ion recombination are briefly discussed.