[en] The distribution function of electron thermalization distances in a liquid under irradiation can be deduced from measurements of free ion yields under wide ranges of applied electric field strength and temperature. The results are analyzed with the aid of an Onsager model. In hydrocarbons and perfluorohydrocarbons the distribution is a three-dimensional Gaussian. In liquid nitrogen and liquid carbon monoxide the distribution is an one-dimensional exponential. In the latter liquids, when the energy of an electron is still well above thermal energy, the electron becomes captured by a molecule, forming a negative ion