Which is the principal law of photochemistry?
Grotthuss–Draper law and Stark-Einstein law The first law of photochemistry, known as the Grotthuss–Draper law (for chemists Theodor Grotthuss and John W. Draper), states that light must be absorbed by a chemical substance in order for a photochemical reaction to take place.
What is the definition for photochemistry?
Definition of photochemistry 1 : a branch of chemistry that deals with the effect of radiant energy in producing chemical changes. 2a : photochemical properties the photochemistry of gases. b : photochemical processes photochemistry of vision.
What is grothus law?
photochemistry. In radiation: Photochemistry. The first, the Grotthuss–Draper law (named for the chemists Christian J.D.T. von Grotthuss and John W. Draper), is simply: for light to produce an effect upon matter it must be absorbed.
What are the two laws of photochemistry?
• The first law of photochemistry, the Grotthuss-Draper law, states that light must be absorbed by a compound in order for a photochemical reaction to take place. • The second law of photochemistry, the Stark-Einstein law, states that for each photon of light absorbed by a chemical system, only one molecule is activated for subsequent reaction.
What is the Stark-Einstein law of photochemistry?
• The second law of photochemistry, the Stark-Einstein law, states that for each photon of light absorbed by a chemical system, only one molecule is activated for subsequent reaction. This “photoequivalence law” was derived by Albert Einstein during his development of the quantum (photon) theory of light.
What is photo excitation and photochemistry?
Photochemistry is also destructive, as illustrated by the photodegradation of plastics. Photoexcitation is the first step in a photochemical process where the reactant is elevated to a state of higher energy, an excited state.
What is meant by photochemistry?
Generally, this term is used to describe a chemical reaction caused by absorption of ultraviolet ( wavelength from 100 to 400 nm ), visible light (400–750 nm) or infrared radiation (750–2500 nm). In nature, photochemistry is of immense importance as it is the basis of photosynthesis, vision, and the formation…