Atomic electron transition

In atomic physics and chemistry, an atomic electron transition (also called an electronic (de-)excitation, atomic transition, or quantum jump) is a change (or jump) of an electron from one energy level to another within an atom[1] or artificial atom.[2] It appears discontinuous as the electron "jumps" from one quantized energy level to another, typically in a few nanoseconds or less.

Electron transitions cause the emission or absorption of electromagnetic radiation in the form of quantized units called photons. Their statistics are Poissonian, and the time between jumps is exponentially distributed.[3] The damping time constant (which ranges from nanoseconds to a few seconds) relates to the natural, pressure, and field broadening of spectral lines. The larger the energy separation of the states between which the electron jumps, the shorter the wavelength of the photon emitted.[4] The emitted photon changes the kinetic energy of the atom, enabling the laser cooling technology to slow down the motion of atoms.