Marcus–Coltrin path
A path trajectory over a potential-energy (reaction) surface which corresponds to the outermost vibrational turning points for the molecular species involved. This path was suggested as a device for calculating the probability of quantum-mechanical tunnelling: the trajectory for the system is considered to follow this path.
PAC, 1996, 68, 149. 'A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)' on page 172 (