A set of collisions between reactant molecules in solids, liquids or dense gases, occurring in rapid succession as a result of the cage effect.
Source:
PAC, 1996, 68, 149. 'A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)' on page 163 (https://doi.org/10.1351/pac199668010149)