Re: radioactivity

[Leigh Palmer <palmer@SFU.CA>]

> Is there not a functional relationship between the decay constant
> and the energy
> of the emitted alpha?


Yes. It is one of the steepest empirical relations in physics.


> Are not all alphas mono-energetic?


Not all nuclides decay by emission of monoenergetic alphas. The
daughter nuclides will be in different states of excitation for
different alpha particle energies. Of course energy conservation
must be satisfied.


> If the above is true, would not one be able to predict the decay constant
> knowing the dimensions of the energy barrier and the alpha energy?


Yes. That is Gamow's contribution. It is now a standard exercise
in elementary quantum mechanics courses and in nuclear physics
courses as well.

Another contributor has taken issue with details in my earlier
posting. I should note that the piece was intended to explain the
phenomenon at a high school level, as that is whence the question
arose. In that context one would not say the strong force makes a
uranium 238 nucleus *metastable* against decay. The strong force
is sufficiently strong to stabilize the nucleus against decay;
such decay is classically forbidden. I wouldn't use the term
metastable in this context.

Leigh