AbstractThe available RRKM programs which cover the full pressure range (high → low‐pressure limits) were written for nonreversible reactions. For reversible reactions the correct shapes of the fall‐off curves can be estimated by applying a correction factor to the RRKM bimolecular rate constant, which depends on a ratio of state densities at the potential maximum. It is proposed that the analysis of such systems in terms of relaxation kinetics provides a more rational treatment, free of the ambiguities associated with specifying a “transition state.”