What is the mole fraction of hexane?

Stable excess electrons have been recently observed in liquid hydrocarbons after suitable purification, but the mobilities indicated the existence of short-lived electron traps in the liquids. We have measured electron mobilities in mixtures of n-hexane and neopentane and find that the mobility is given accurately by an expression of the form ?=?nexp(-xhE / kT), where xh is the mole fraction of hexane. It is concluded that the trap cannot be a negative-ion state of a single molecule, but is instead a collective trap involving several fluid molecules.