Electron Energy Transitions

quantum:  a discrete quantity of energy that cannot be divided.

ground state:  the lowest available energy level for an electron.

excited state:  a higher energy level than the ground state.

emission spectrum:  the wavelengths (colors) of light emitted by an element when its electrons are “excited” (raised to a higher energy state) and then allowed to return to the ground state.

Hydrogen:

Iron:

photon: a single “piece” (particle/wave) of light.

luminescence:  light that is not generated by high temperatures alone.  (In fact, it usually occurs at low temperatures.  Causes include electrical energy and chemical reactions .

fluorescence:  a type of luminescence that occurs when electrons of an element are excited and return immediately to the ground state, giving off a photon.  The wavelength of the photon given off is usually different from the wavelength of the photon used to raise the electrons to the excited state.

phosphorescence:  “glow-in-the-dark” luminescence—a type of luminescence that occurs when electrons are excited, but cannot return directly to the ground state.  The indirect path is slower, which cause the material to “glow” for a longer period of time (in some cases, hours).

triboluminescence:  a form of luminescence in which light is generated by breaking asymmetrical bonds in a crystal.  In the case of wintergreen Life Savers, when the sugar crystals are crushed, the positive and negative charges get separated.  The voltage between them causes a spark.  Normally, these sparks are in the ultraviolet part of the spectrum and cannot be seen; however, wintergreen oil (methyl salicylate) is fluorescent.  It absorbs the photons of ultraviolet light and emits photons of blue light, which we can see.