The vast difference between electron mobilities in isomeric pentane liquids is explained on the basis of Anderson localization followed by trapping. Random site energy fluctuation is modeled on electron-anisotropic polarizability interaction with the molecules. Connectivity and intermolecular separation are obtained from X-ray scattering data. Together, these parameters determine the fraction of initially delocalized states, computed to be 0%, 61.4%, and 100%, respectively, for n-, iso-, and neo-pentane. Trap depths and densities are phenomenologically rationalized with observed mobilities. The values for trap depths are 0.17, 0.11, and 0.02 eV for n-, iso-, and neo-pentane, while the corresponding trap densities are 0.45 x 10(19), 0.70 x 10(19), and 0.23 x 10(19) cm (3), respectively. (C) 2009 Elsevier B.V. All rights reserved.