A Reexamination of the Derivation of the Equilibrium Supersaturation Curve for Soluble Particles

Abstract

In this derivation of the equilibrium supersaturation curve for soluble particles, Köhler treated the van't Hoff factor as a constant. McDonald points out that this factor is actually a function of the droplet molality. In this paper, we have rederived equilibrium supersaturation relation following Köhler's approach, except that the van't Hoff factor is treated as a variable in the derivation. The resulting equation is considerably more complicated than the result obtained by Köhler. A simple substitution of a variable van't Hoff factor into Köhler's familiar equation that was derived assuming a constant van't Hoff factor results in a fairly significant error.