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 (λ) is written as the sum of an inner contribution (λin) and an outer contribution (λout) attributed to nuclear reorganizations of the redox partners and their environment (solvent), respectively.