Abstract
Measurements of the Hall and the time-of-flight mobilities of electrons injected into neopentane along the liquid-vapor coexistence curve between the triple and the critical points are reported. The ratio of the Hall mobility to time-of-flight mobility always exceeds unity; it decreases linearly from 1.8 at low temperatures to 1.4 near 410 K and increases thereafter to nearly 5.8 in the vicinity of the critical point. This is suggestive of localized states associated with density fluctuations. These density fluctuations are probably the dominant scattering mechanism that determines the Hall mobility.