Photoionization processes in nonpolar media: Density effect

Abstract

Recently, values of photoionization threshold energy I p have been measured as a function of host density in nonpolar fluids doped with guest atoms or molecules with low ionization potential. In this paper, we review the photoionization mechanisms proposed in an attempt to explain the density dependence of I p values, and discuss Rydberg states in high pressure gases, liquids and supercritical fluids.