A chemical process in which the reactive complex
has a lifetime
that is shorter than its period of rotation. In a molecular-beam
experiment the reaction products of a direct reaction are scattered, with reference
to the centre of mass of the system, in preferred directions rather than at random.
Some direct reactions are impulsive which means that there is an energy exchange that
is very fast compared to the vibrational time scale. A direct reaction is to be contrasted
with an indirect reaction
, also known as a complex-mode reaction
PAC, 1996, 68, 149
(A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC
on page 163
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. https://doi.org/10.1351/goldbook