threshold energy, \(E_{0}\)

https://doi.org/10.1351/goldbook.T06366
Potential energy gap between @[email protected] and the @[email protected], sometimes involving the zero point energies, but usually not.
See also:
critical energy
Sources:
Green Book, 2nd ed., p. 56 [Terms] [Book]
PAC, 1996, 68, 149. (A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)) on page 189 [Terms] [Paper]