Gibbs energy dissipated when a system that has undergone 'vertical' electron transfer (i.e., electron transfer obeying the Franck–Condon principle) relaxes to the equilibrium state for its new charge distribution. Commonly the total reorganization energy ($\lambda$) is written as the sum of an inner contribution (${\lambda }_{\text{in}}$) and an outer contribution (${\lambda }_{\text{out}}$) attributed to nuclear reorganizations of the redox partners and their environment (solvent), respectively.