isotope effect

Also contains definition of: equilibrium isotope effect
https://doi.org/10.1351/goldbook.I03327
The effect on the rate or @E02177@ of two reactions that differ only in the isotopic composition of one or more of their otherwise chemically identical components is referred to as a @K03405@ or a @T06319@ (or equilibrium) isotope effect, respectively.
Sources:
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1130 [Terms] [Paper]
PAC, 1994, 66, 2513. (Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994)) on page 2521 [Terms] [Paper]