Point of intersection between the potential energy surfaces of states of different multiplicity.
The intersection belongs to a
subspace of the
)-dimensional nuclear coordinate space and therefore appears
as a line on a two-dimensional energy surface
is the number of nuclei).
In this case the branching plane
is one-dimensional and is defined by the gradient
PAC, 2007, 79, 293
(Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006))
on page 421
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. doi:10.1351/goldbook