BRANCHING RATIOS IN ACTIVATED SYSTEMS

Branching between reaction channels in activated systems is often obse rved to vary with changes in the potential energy surface as Delta ln( k(1)/k(2)) proportional to Delta(Delta E(1)(double dagger) - Delta E(2 )(double dagger)). RRKM calculations demonstrate that in many, but not all, cases the log-linear relationship accurately describes branching in nonthermal distributions of reactants with energies well above the threshold for reaction. The origin of this relationship and condition s necessary for its validity can be understood in terms of quantum RRK theory.