Many photochemical processes occur in nature. Let us quote some examples:

• At the time of the Photosynthesis of the house plants, the molecules of the Pigment Chlorophylle absorb the Photon S of solar light and provide energy allowing the Synthèse Glucide S.

• the photodissociation of the Ozone in the atmosphere is supported by solar light. The Ozone absorbs this light and thus contributes to protect us from the ultraviolet rays.

• photography is a photochemical process. Indeed, the Bromure of money is transformed into metal Argent under the action of the light.

• the process of vision utilizes the photochemical isomerization of the Rhodopsine in the Rétine of the eye.