väriainemolekyyliin

A colorant molecule, or väriainemolekyyli in Finnish, is a chemical compound that selectively absorbs certain wavelengths of visible light and reflects or transmits others. This selective absorption and reflection of light is what gives a substance its color. The specific arrangement of atoms and the electronic structure within the molecule determine which wavelengths of light are absorbed and which are not. These molecules are the fundamental components responsible for the coloration of dyes, pigments, and other colored materials.

The interaction of light with a colorant molecule occurs when photons of light strike the molecule. If the energy of a photon matches an energy difference between electron orbitals within the molecule, the electron can absorb the photon and move to a higher energy level. The wavelengths of light that are absorbed are those whose photon energies correspond to these electronic transitions. The wavelengths that are not absorbed are either reflected by the surface of the material or transmitted through it. The combination of the reflected or transmitted wavelengths is what our eyes perceive as color.

The structural features that enable a molecule to absorb visible light are often related to the presence of conjugated systems, which are alternating single and double bonds, or other electron-donating and electron-withdrawing groups. These features create a delocalized electron system that can readily absorb energy from photons. The size and extent of the conjugated system, as well as the specific atoms involved, influence the specific wavelengths of light that are absorbed, thereby dictating the observed color.