Figure 1. Jablonski diagram, depicting generic state energies

The Jablonski diagram charts the processes that a light absorbing molecule undergoes after simultaneously absorbing a photon and (1) jumping to the singlet excited state, and either returning to the ground state (7,8,9) or becoming a reactive intermediate (10). The processes depicted are: photon absorption and orbital jump (1); vibrational relaxation (2); internal conversion (3); fluorescence (4); singlet quenching (5); intersystem crossing from the singlet excited state to the triplet excited state (6); phosphorescence (7); intersystem crossing from the triplet excited state to the ground state (8); triplet quenching (9); and photochemical transformation to a reactive intermediate (10).