I'm a physicist. While visiting someone's o-chem class I learned about the existence of the deuterium kinetic isotope effect. This seems like an extremely sweet example of zero-point energy, and I would like to use it as an example when teaching the basic quantum mechanics that we teach in freshman physics at a community college.

In this context, I would like to be able to give a good example where we actually care about the deuterium kinetic isotope effect. Ideally this would be an example that would be at least somewhat understandable to people who (like me) have no clue about organic chemistry. Something like:

  • Without the deuterium kinetic isotope effect, we wouldn't be able to synthesize x (where x is nail polish, fullerenes, methamphetamine, ...)

  • Historically, there was intense controversy about how this mysterious chemical process in x worked (where x is learning in slime molds, work-hardening of bronze, ...), but then they injected their (slime mold, ...) with deuterium and used the deuterium kinetic isotope effect to prove that ...

Related: Why is a C–D bond stronger than a C–H bond?

  • 1
    $\begingroup$ Involvement of water in enzyme-based catalysis, I'm sure there are examples. $\endgroup$
    – TAR86
    Oct 18, 2019 at 5:39
  • $\begingroup$ The effect can be smaller that you imagine as the energy at the transition state may also be lowered so the barrier height need not change that much. In reactions involving many steps, particularly with enzymes a small, say 10%, change at each step becomes important and results in a big overall effect. $\endgroup$
    – porphyrin
    Oct 18, 2019 at 8:06
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    $\begingroup$ You might read about heavy water toxicity to find an overall impressive one. For instance an aquarium of heavy water can host no fishes, at least after a certain time. $\endgroup$
    – Alchimista
    Oct 18, 2019 at 10:24
  • $\begingroup$ @porphyrin "Big" is relative. I dont think there is a natural reaction pathway that can actually accumulate deuterium in a specific chemical function to twice the concentration in the surrounding water or so. Much less, usually. $\endgroup$
    – Karl
    Oct 18, 2019 at 16:57
  • $\begingroup$ The site specific hydrogen (and carbon) isotope ratios tell you if the alcohol in your wine was actually made by fermentation of fructose (instead of saccharose, maltose, ...), and even if the fructose was actually in grapes and not apples. en.wikipedia.org/wiki/…. $\endgroup$
    – Karl
    Oct 18, 2019 at 17:04


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