Chemilluminescence

Chemiluminescence

This is the chemical reaction that occurs in a glow stick. There are three components of a lightstick. There need to be two chemicals that interact to release energy and also a fluorescent dye to accept this energy and convert it into light. Although there is more than one recipe for a lightstick, a common commercial lightstick uses a solution of hydrogen peroxide that is kept separate from a solution of a phenyl oxalate ester together with a fluorescent dye. The color of the fluorescent dye is what determines the resulting color of the lightstick when the chemical solutions are mixed. The basic premise of the reaction is that the reaction between the two chemicals releases enough energy to excite the electrons in the fluorescent dye. This causes the electrons to jump to a higher energy level and then fall back down and release light. Specifically, the chemical reaction works like this: The hydrogen peroxide oxidizes the phenyl oxalate ester, to form phenol and an unstable peroxyacid ester. The unstable peroxyacid ester decomposes, resulting in phenol and a cyclic peroxy compound. The cyclic peroxy compound decomposes to carbon dioxide. This decomposition reaction releases the energy that excites the dye.

One of the main applications of chemiluminescence is in determining small amounts of poisons or impurities in air.

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One of the oldest known chemoluminescent reactions is that of elemental white phosphorus oxidizing in moist air, producing a green glow. This is a gas-phase reaction of phosphorus vapor, above the solid, with oxygen producing the excited states (PO)2 and HPO.
 * Gas Reactions:**

Another gas phase reaction is the basis of nitric oxide detection in commercial analytic instruments applied to environmental air-quality testing. Ozone is combined with nitric oxide to form nitrogen dioxide in an activated state. NO+O3 → NO2[◊]+ O2

Liquid-phase reactions Luminol in an alkaline solution with hydrogen peroxide in the presence of iron or copper, or an auxiliary oxidant, produces chemiluminescence. The luminol reaction is: luminol + H2O2 → 3-APA[**◊**] → 3-APA + light