INTEGRAL EQUATION STUDY OF THE CORRELATION LENGTHS IN IONIC FLUIDS

Abstract

The restrict primitive model of ionic systems is investigated with the integral equation theory. Using the correlation functions calculated in the reference hypernetted chain approximation, we get (i) the Lebowitz lengths at different densities and temperatures, (ii) the density–density correlation lengths along different isochores approaching the spinodal curve from above. The Lebowitz length obtained by us has better agreement with the Monte Carlo simulation results than the generalized Debye–Hückel theory. Along the critical isochore, the Lebowitz length remains finite when approaching the critical temperature from above, while the density–density correlation lengths diverge as t-1/2 with t = (T - Ts)/Ts, where Ts is the temperature on the spinodal line.