Band-hopping mobility transition in naphthalene and deuterated naphthalene

Measurements of the mobility, whose temperature dependence suggests a band-hopping transition is occurring near 100 K, are reported for electrons in the $c^{\prime }$ and $b$ directions of naphthalene and the $c^{\prime }$ direction of deuterated naphthalene. A review of the status of the theoretical understanding of this transition indicates that while progress is being made toward understanding the hopping mechanism of transport, significant aspects of these data remain unexplained.