Thermally averaged effective dissociation energy of dimers

The dissociation energy of highly excited dimers is averaged over the regions of strictly bound, metastable and free states in the phase space. It is demonstrated that a substantial decrease of the effective dissociation energy can be expected for weakly bound dimers and conventional diatomics held respectively at normal or extremely high temperatures. Estimates are given for the two-temperature scheme. The role played by the formation of metastable dimeric states is discussed.