A form of the
collision theory of chemical reactions in which the assumption is made that reaction can only occur
if on collision the component of energy along the line of centres of the masses of
the colliding species is greater than a particular
threshold energy.
Source:
PAC, 1996, 68, 149
(A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC
Recommendations 1996))
on page 171