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Atomic Disguise Makes Helium Look Like Hydrogen
An anonymous reader writes "In a feat of modern-day alchemy, atom tinkerers have fooled hydrogen atoms into accepting a helium atom as one of their own, reports New Scientist. Donald Fleming of the University of British Columbia in Vancouver, Canada, and colleagues managed to disguise a helium atom as a hydrogen atom by replacing one of its orbiting electrons with a muon, which is far heavier than an electron. The camouflaged atom behaves chemically like hydrogen, but has four times the mass of normal hydrogen, allowing predictions for how atomic mass affects reaction rates to be put to the test."
As I recall, the poor muon has an average lifetime of something like 2 microseconds. We might see some interesting theoretical chemistry come out of this (the reaction-rate question) but it looks like we'll end up a little light on practical applications of muons in chemical compounds.
The World Wide Web is dying. Soon, we shall have only the Internet.
This is super cool, but less for the kinetic isotope effect (KIE) studies and more for the muon-electron substitution. We've compared isotope masses with reaction rates using deuterium and tritium before, so using "H-4" and "H-5" is nice for extended validation, but not unexpected. The muonium is pretty bad-ass, though.
If you want a vision of the future, imagine a youtube comments section scrolling - forever.
does it make your voice go higher or lower when inhaled?
So what's interesting is that they were able to do this at all -- either they found a way to extend muon life (unlikely, or that would be the main news here), or they worked insanely fast to get their results before the decay.
Why guess when you can know? Measure!
I remember that much past interest over muons and hydrogen has been around muon-catalyzed fusion. As you say, the muons are quite short-lived, which prevents them from catalyzing enough H-H fusions to get to breakeven. And then there was the alpha-sticking problem, whereby helium nuclei products then grab the muons, thus stealing them away from the process.
Check out ultra-dense deuterium, though. It's some kind of exotic form of matter, and there have recently been some tantalizing glimpses of it in nano-sized clumps.
I come in last night about half past ten,
That hydrogen wouldn't let me in.
So muon on over. Rock it on over.
Move over little atom, a mean, old atom's muon in.
Program Intellivision!
There's no helium shortage. There's shitloads of it over there *waves in direction of Jupiter*
Fleming's team shot muons produced at the TRIUMF accelerator in Vancouver into a cloud of helium, molecular hydrogen and ammonia. The helium atoms captured the muons, then pulled hydrogen atoms away from the molecular hydrogen and bonded with them.
This was all done at TRIUMF, the world's largest cyclotron and by far the best particle accelerator in Canada. Plus, Donald Truhlar (a giant in the field) supported the experimental rate constants with quantum mechanical predictions - very neat stuff indeed!
Hey mate, spare a sig?
Rule #1: the joke has to be funny, at least funnier than the explanation, which is not the case here.
The atom has no physical shape. If the p1 orbital occupied by the single electron is similar enough "chemically", the effective radius will also be identical.