A quantity derived from the pressure dependence of the
rate constant of a reaction (mainly used for reactions in solution),
defined by the equation:
providing that the rate constants of all reactions (except first-order reactions)
are expressed in pressure-independent concentration units, such as

at a fixed temperature and pressure. The volume of
activation is interpreted, according to
transition state theory, as the difference between the partial molar volumes of the
transition state (

) and the sums of the partial volumes of the reactants at the same temperature and
pressure, i.e.
where

is the order in the reactant R and

its
partial molar volume.
Source:
PAC, 1994, 66, 1077
(Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994))
on page 1175
Cite as:
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.