J. CHEM. SOC. FARADAY TRANS., 1994, 90(16), 2353-2358 2353

Does Mass Action Law Breakdown Occur in Small Thermodynamic Systems ?

Artjom V. Sokirko*

A. N. Frumkin Institute of Electrochemistry, Russian Academy of Sciences, 117071 Moscow, Russia

The problem of applicability of the mass action law to very small thermodynamic systems originally studied by L. A. Blumenfeld, A. Yu. Grosberg and A. N. Tikhonov, J. Chem. Phys., 1991, 95, 7541 is critically analysed. A more general statistical mechanics model and a simple kinetic model, which yields results that include those of Blumenfeld et al. as a special case, are proposed. It is shown that in order to obtain, in practice, the mass action law breakdown predicted by Blumenfeld et al., it is necessary either to consider a non-equilibrium thermodynamic system or to include a non-thermodynamic mechanism, e.g. Maxwell's demon. Conditions for which a statistical function can describe the behaviour of a small thermodynamic system in an adequate way are discussed.