Assertion: deuterium's effect | /r/HasProperty | no tunneling
Facets:
Source sentences:
text: D ~ 10 is thought to be maximal for a semi-classical primary kinetic isotope effect (no tunneling) for reactions taking place around 298 K. (The formula for k H /k D has a temperature dependence, so larger isotope effects are possible at lower temperatures).
text: In rare cases where a quantum mechanical effect called tunneling occurs in the reaction, deuterium isotope effects of 20 or more have been observed.