Atomic electron transition

In atomic physics and chemistry, an atomic electron transition (also called an atomic transition, quantum jump, or quantum leap) is an electron changing from one energy level to another within an atom or artificial atom. These energy levels are discrete, quantized, and obtain unique energy gaps specific to a given atom. Though not an exhaustive list, energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) are a few of the many characterization techniques that employ the "atomic fingerprint" phenomenon of atomic electron transitions obtained by the unique quantized energy levels to identify atomic presence and relative composition within samples.

Electrons can relax into states of lower energy by emitting electromagnetic radiation in the form of a photon. Electrons can also absorb passing photons, which excites the electron into a state of higher energy. The larger the energy separation between the electron's initial and final state, the shorter the photons' wavelength.