A mechanism that sometimes applies to the combination of atoms, but rarely of free radicals. In this mechanism the atom A first combines with a third body or chaperon,
and the complex AM
then forms A2
by collision with another atom A
Contrast the energy-transfer mechanism.
PAC, 1996, 68, 149. 'A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)' on page 153 (https://doi.org/10.1351/pac199668010149)