Space Forum / Space Science / January 2008

-> Convince the calculation and measurement of bismuth half-life,
 
Actually, there is one (rather rare) mode of radioactive decay that can
be speeded up or slowed down by changing the chemical environment of
the element. It's called "electron capture". An electron from the
environment enters the nucleus, and turns it into a nucleus with
one-smaller positive charge, i.e. into a nucleus of the preceding
element, which may or may not then decay further. The rate of electron
capture depends on the density of electrons in the vicinity of the
nucleus, which depends on how the atom is chemically bonded.
 
Naturally-occurring bismuth is not radioactive, and therefore does not
have a half-life. It consists entirely of the isotope with mass 209.
However, there are some lighter isotopes that can be made artificially
which do decay by electron capture. So the rates of decay of these
isotopes could be varied chemically.
 
This has nothing to do with dating, of course. The elements that are
used for this do not decay by electron capture.
 
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