Assuming the initial and final state are well separated, the Franck-Condon factors decay exponentially with the energy gap between the two levels . The temperature dependence and activation energy in an Arrhenius-like examination of internal conversion is highly semi-empirical, and is defined by the formation or cleavage of chemical bonds. The prediction properties are taken from fitting parameters of experimental data in the form of a pre-exponential factor A IC and the internal conversion activation energy E A . This can be cast as :