The commercial lightstick contains dilute hydrogen peroxide in a phthalic ester solvent contained in a thin glass ampoule, which is surrounded by a solution containing a phenyl oxalate ester and the fluorescent dye 9,10-bis(phenylethynyl)anthracene. When the ampoule is broken, the hydrogen peroxide and oxalate ester react. During the course of the reaction, an intermediate is produced which transfers energy to the dye molecule. Visible light is emitted when the excited dye molecule returns to the ground state.