Effects of Details of Dynamics on dc Transport Coefficients in Solution

We consider, within the framework of Liouville's equation, the calculation of a simple higher-order transport coefficient, the Hall conductance. We show that this quantity can be resolved into two terms. One is the first moment of the time-relaxed momentum correlation function of the carrier in the field-free system while the other, an intrinsically non-Markoffian contribution, is not simply a functional of this correlation function. The latter term does not appear in earlier work. We show that it vanishes in limiting cases corresponding either to a dilute plasma or the converse extreme corresponding to ions in a dense, strongly interacting solvent.