[wereworm73]

I found this interesting article from Physics Web at http://physicsweb.org/articles/news/8/9/12


After reading it, I was wondering if trapping radioactive atoms inside cryptands could speed up the electron-capture decay rate even further.  Since cryptands can be smaller than C₆₀ and have lots of lone pairs, I think it could put a tighter squeeze on the electrons surrounding the trapped nucleus.  Or maybe even ultrasound used in sonoluminescence experiments would do the trick (I'm not sold on "bubble fusion", though the temperature & pressure within the bubbles are still pretty incredible.)

What do you think?

[Mitch]

Probably could, but these effects are really really small. Electron capture usually involves the 1s electrons predominantly, and its hard "chemically" to do Chemistry with inner electrons in general.

[wereworm73]

Hmmm...if trying to shove an inner electron into the nucleus doesn't work so well, then maybe agitate the nucleus a bit with, say, gamma rays (so a proton gets nudged precariously close to an inner electron)?   

[Mitch]

Berrylium has a radius of roughly 3 femtometers. The Borh radius for a 1s electron in hydrogen is 50 picometers, that's a rather large and unlikely nudge.

[wereworm73]

A little follow-up here...Apparently, EC decay is slower if the radioactive atoms are embedded in metals at very low temperatures. 

http://physicsweb.org/articles/news/10/7/13/1

[pantone159]

Personally, I am suspicious of these claims.
Reducing the half-life of Ra-226 (an alpha emitter) from 1600 years to 1 year???

That is pretty dramatic.

[Borek]

Personally, I am suspicious of these claims.
Reducing the half-life of Ra-226 (an alpha emitter) from 1600 years to 1 year???

That is pretty dramatic.

And hardly believable that such effect was not spotted earlier.

[wereworm73]

Yeah, it would be nice to see the data & calculations from the original paper.  I would think putting radioactive atoms inside a metal at 4 K would actually encourage electron capture to some degree (like the radioisotope-in-a-buckyball experiment above).  Still, I have to give them credit for coming forward with such radical claims instead of just throwing out their data--and quite possibly a breakthrough--to protect their reputation with the scientific community.

[pantone159]

Some effect on electron-capture cross-sections is plausible (this has been observed before),
as chemical changes can indeed affect the probability of electrons being at the nucleus.
These effects have been very small, however.

But alpha emitters?  And a factor of 1600 change???