Electron thermalization-distance distributions in electron-attaching fluids

The electron ejected from a molecule by an energetic impact moves away from the resultant ion and loses energy to the molecules with which it collides. The distance such electrons travel away from their ions during thermalization can be estimated by measuring the free-ion yields as a function of electric-field strength. This was done in gaseous and liquid carbon disulfide and hexafluorobenzene over wide ranges of densities. The electron thermalization-distance distribution in C6F6 was the same as that in most other liquids; it was a Gaussian distribution with a power tail. However in liquid CS2 the distribution was different, an exponential with a power tail, as in liquid nitrogen and liquid carbon monoxide. The different distributions reflect differences in the thermalization processes. The thermalizing ability of both CS2 and C6F6 is less in the liquid than in the gas. There is an especially sharp decrease in the thermalizing ability of CS2 at the highest densities.