Chemical Fluctuations

Abstract

The fluctuations of the progress variables χ _r around their averages may be called “chemical fluctuations”. A measure of such fluctuations are the correlations 〈Δχ _r Δχ _s 〉, which are given in terms of the susceptibilities by

$$\left\langle {\Delta {x_r}\Delta {x_s}} \right\rangle = kT\frac{{\partial {x_r}}}{{\partial {\alpha _s}}}.$$

((25.1))