Qualms regarding the range of validity of the glansdorff-prigogine criterion for stability of non-equilibrium States.

Doubt is raised concerning the range of validity of a stability criterion for non-equilibrium states which has been proposed by Glansdorff and Prigogine. In the case of a particular autocatalytic reaction, the stability analysis presented by Glansdorff and Prigogine, and by Eigen and by Katchalsky in their reviews of this problem, does not agree with our analysis, which is based upon exact solution of the relevant rate equations. We also find disagreement between the analysis based upon the Glansdorff-Prigogine criterion and our analysis of a second example which involves non-equilibrium steady states. The situation is quite delicate because seemingly innocent approximations (e.g., the use of specialized conditions in the autocatalytic reaction X + Y right arrow over left arrow 2X discussed in the sequel) may lead to the impression that the scope of validity of the criterion is wider than it actually is. By considering the stability of the equilibrium state, we conclude that the second differential of the entropy, which is at the heart of the Glansdorff-Prigogine criterion, is likely to be relevant for stability questions close to equilibrium only.