The activation energy,Ea taken from the thermal decomposition of KMnO4 and AgMnO4 was compared with the energy of the longest wavelength O→Mn ‘charge transfer’ (CT) transition. TheEa and CT correlation was found in these systems. However, such relationship can be valid when in the dissociation process the
electron transfer is assumed to be the rate determining step. Thus, the permanganates as well as the previously studied chromates,
are positive examples showing that in some cases, the energies derived from both methods can be comparable.