The Chemistry Behind Luminescence: Photochemistry
By Sai Prasanna Thapa Chemistry Department As a child, I always wondered what made fireflies glow by night, and the seashores of Puerto Rico engulfed in radiant blue tides. Nature seems to have its magic to make things glow, but there is also Science behind it. Photochemistry is a branch of Physical Chemistry that deals with the emission or absorption of radiation. It includes mainly two types of processes—namely, Photophysical processes and Photochemical reactions. Photophysical processes take place in the presence of light without involving any chemical reactions. They occur due to the absorption of light by various substances, followed by the emission of the absorbed light. Photochemical reactions occur by absorption of radiations of an appropriate wavelength. There are chiefly three phenomena that cause Nature to glow: Chemiluminescence, Fluorescence and Phosphorescence. These three together are called Luminescence. As aforementioned, light is absorbed when a photoche