Within a generating function regime (Equation ), one can calculate the rate of internal conversion in quantum dots. Consider a system within a strong coupling regime: here the sum of the average number of phonons N j is much greater than one ( j N j ≫ 1). If we then apply a Fourier transform to the delta function, we can truncate the expansion with respect to each respective frequency at the second-order term . The rate of internal conversion in quantum dots can then be expressed as :