Re: Nuclear decay

[David Bowman <David_Bowman@GEORGETOWNCOLLEGE.EDU>]

Regarding John Cooper's question:
>  Conventional answer is "NO"
>  Anyone know otherwise?

The negative conventional answer is correct assuming that we are really
concerned about nuclear *decay*, which is not a thermally activated
process, and is instead, typically, a quantum tunnelling-like process
whose relevant energy scale is on the order of MeV (1 eV = 11604 K).

Other (not decay) nuclear reactions that *are* thermally activated
require (by definition) *thermonuclear* temperatures to initiate, modify
their rates, and/or affect their equilibrium species concentrations.

There are a few radioactive nuclides whose so-called "decay" rates *can*
be very slightly affected by extreme pressures and temperatures.  These
nuclides "decay" via electron K-capture.  Thus, any environmental
conditions that are severe enough to slightly perturb the inner K
electrons' core orbital state wave function enough to affect its overlap
with the nucleus will affect the rate of capture from that core state.
Typically such conditions are *much* too extreme to be found in a mere
forest fire. (For instance, megabar level pressures are typically needed
as I recall).

But K-capture is not strictly a *nuclear decay*.  It is a joint reaction
between orbital electrons and a nucleus.  If such an atom was fully
ionized as a bare nucleus it would be stable since there would be no
electron to capture.

> Date: Tue, 11 Jul 2000 11:59:00 -0700
> From: Robert W. Zoellner <rwz7001@humboldt.edu>
> To: chemed-l@atlantis.uwf.edu
> Subject: Nuclear decay
>
> Greetings All,
>
> A question came up as a follow-up to the recent fire at New Mexico's Los
> Alamos National Laboratory that I could not answer.  I'm hoping that
> someone out there can do so:
>
> Are rates of nuclear decay affected by changes in temperature?  That is,
> as with other first order reactions, if you raise the temperature, does
> the rate increase?  My immediate response was that the effect of
> temperature would be negligible given the energies involved, but on second
> thought decided that the temperature effect would depend upon the
> activation energy, and I had no clue as to the magnitude of that barrier.
> So ... can you speed up nuclear decay by raising the temperature for
> temperatures attainable in a laboratory setting ... or in the sun ...
> etc.?

David Bowman
David_Bowman@georgetowncollege.edu