Are there any charts (information) concerning the elements and Atomic Electron Transition intervals? Does each element have a time it takes from absorption to the time of re-emission? Concerning Spectral Lines are the result of interaction between a quantum system (atoms) and a single photon. When a photon has about the right amount of energy to allow a change in the energy state of the system (in the case of an atom this is usually an electron changing orbitals, the photon is absorbed. Then it will be re-emitted either in the same frequency as the original or in a cascade, where the sum of the energies of the photons emitted will be equal to the energy of the one absorbed (assuming the system returns to its original state).