DOES MASS-ACTION LAW BREAKDOWN OCCUR IN SMALL THERMODYNAMIC SYSTEMS

The problem of applicability of the mass action law to very small ther modynamic systems originally studied by L. A. Blumenfeld, A. Yu. Grosb erg and A. N. Tikhonov, J. Chem. Phys., 1991, 95, 7541 is critically a nalysed. A more general statistical mechanics model and a simple kinet ic 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 thermodynam ic system or to include a non-thermodynamic mechanism, e.g. Maxwell's demon. Conditions for which a statistical function can describe the be haviour of a small thermodynamic system in an adequate way are discuss ed.