Activation

Name:
Activation
Detailed information:
The process of treating a substance or a molecule or atom by heat or radiation or the presence of another substance so that the first-mentioned substance, atom, or molecule will undergo chemical or physical change more rapidly or completely. Common types of activation are: (1) Processing of carbon black, alumina, and other materials to impart improved adsorbent qualities. Subjecting the material to steam or carbon dioxide at high temperatures is the method usually used.See Alumina, Activated; Carbon, Activated. (2) Heating or otherwise supplying energy to a substance (for example, ultraviolet or infrared radiation) to attain the necessary level of energy for the occurrence of a chemical reaction, or for emission of desired light waves, as in fluorescence or chemical lasers. The term excitation is also used. (3) An important variation of (2) is the process of making a material radioactive by bombardment with neutrons, protons, or other nuclear particles.See Activation Analysis; Energy, Activation.(4) Catalytic processes in which the energy of activation for occurrence of a reaction is lowered by the presence of a nonreacting substance.