When considering non-adiabatic molecular dynamics simulations in terms of Fermi's Golden Rule (Equation ), Duncan & Prezhdo noted that an approximate relation between the degree of vibronic coupling and the optical band gap could be drawn. Specifically, if the density of states were to be approximated as the the inverse of the energy band between the initially photoexcited electron or hole state and the corresponding bandgap state E optical , respectively, and the perturbative coupling term to be taken as the vibronic coupling V vibronic singularly, then a simplified expression could be used to model the photophysics of a given nanostructure system. This can be cast in a simplified form :