early-downhill surface

https://doi.org/10.1351/goldbook.E01883
See: attractive potential-energy surface
Source:
PAC, 1996, 68, 149. 'A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)' on page 163 (https://doi.org/10.1351/pac199668010149)