Under the assumption that hitting the conical intersection will always result in internal conversion, it can be assumed that the exciton dynamics are dependent on only the barrier energy and vibrational energy of the system. This can be calculated using Kramers' barrier model , which described the crossing of an exciton between two potential energy wells across a barrier, and in simple terms relates the well frequency ω w with the barrier of height E w and frequency ω u within a medium with a friction constant γ F , cast as :