A chain reaction which includes a propagation step or steps in which there is an increase in the number of active intermediates; for example,
B00723-1.png
is a branching reaction since one active intermediate (
H) gives rise to two (
OH and
O).
Source:
PAC, 1981, 53, 753. 'Symbolism and Terminology in Chemical Kinetics' on page 762 (https://doi.org/10.1351/pac198153030753)