photochemistry

There are two “laws” of 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. The second, or Stark–Einstein law (for the…

The principal applications of photochemistry (including photography) are in the initiation of reactions by light that can pass through glass or quartz windows. Such light has a wavelength of not less than about 185 nanometres. Light of shorter wavelength is also effective, but the…

Photochemistry is a specialty that investigates the interaction of light with matter. Chemical reactions initiated by the absorption of light can be very different from those that occur by other means. Vitamin D, for example, is formed in the human body when the steroid ergosterol…