Electron spin catalysis

Spin catalysis was proved to operate in radical recombination, biradical decay, cis-trans isomerization of molecules, low-temperature recombination of spin-aligned hydrogen atoms, spin conversion of positronium atom, primary light-harvesting reactions in photosynthetic centers, paramagnetic quenching of excited molecules among others. Possibly the extent of the phenomenon may be larger than the level of current knowledge. As a driving force of spin conversion in triads, the exchange interaction competes with magnetic interactions in the pairs of spin carriers.