intersection space

https://doi.org/10.1351/goldbook.IT07400

(3N − 8)-dimensional subspace of the (3N − 6)-dimensional nuclear coordinate space consisting of an infinite number of conical intersection points (N is the number of nuclei).

Source:
PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 356 (https://doi.org/10.1351/pac200779030293)