MODEL FOR ASSOCIATIVE-DETACHMENT REACTIONS OF INSERTION TYPE

Exothermic associative-detachment reactions of the bond-insertion type B-+AC→ABC+e or B-+AC→ABC+e may or may not be very fast at 300°K. It is proposed that the slow cases are those which have activation energies and that the occurrence of an activation energy is favored by low exothermicity ΔEnd and by a large nuclear deformation energy ΔEnd. The nuclear deformation energy is defined as the energy required to increase the AC bond length to the value it would have in ABC. This simple criterion, ΔEnd, for existence of an activation energy accounts reasonably well for the five reactions of the insertion type which have so far been measured. Two of the measurements are reported here for the first time.