The secondary kinetic isotope effect (SKIE) arises when an isotopic substitution that is not involved in the reaction influences the internal vibrations of the system that via changes in the zero point energy (ZPE) affect the rates of chemical reactions.
The secondary kinetic isotope effect (SKIE) arises. An isotopic substitution influences the internal vibrations of the system. This system via changes in the zero point energy (ZPE) affect the rates of chemical reactions. This isotopic substitution is not involved in the reaction.