Photodissociation of the Hydroxyl Radical (OH)

The hydroxyl radical (OH) is sort of a piece of a molecule. It is made up of one oxygen atom and one hydrogen atom. One way to make OH is to knock a hydrogen atom off of a water molecule (H2O).

This movie shows how an ultraviolet (UV) photon can break apart the hydroxyl radical. When the photon hits the radical, it adds energy to the radical. The extra energy breaks the bond between the oxygen atom and hydrogen atom. The two atoms fly apart! This is called photodissociation.