Isomers: New way to generate energy

[Karlos]

It's a bit like the nuclear analogue of a chemical mixture which is thermodynamically unstable but kinetically stable.

The excited nuclear state is thermodynamically unstable with respect to it's lower energy ground state, but it has to overcome various strong internal interactions in order to reconfigure. The irradiation gives it the boost it needs to overcome the initial barrier.

In a similar way, a mixture of hydrogen and oxygen is extremely thermodynamically unstable - it would be a much lower energy configuration as water. However, it will sit around indefinately because energy is required to break up the existing molecules such that they can recombine. It doesn't yet have the energy it needs to overcome this - it's kinetically stable.

Now, throw a spark in there and watch it go...

[Karlos]

Agreed - catalysts can be a lot of fun ;-)

A catalyst typically provides a lower energy path for the reaction so you don't need to inject as much energy - or indeed any if the catalysed path provides such a lower path that there is already enough thermal energy in the system to set it off.

I think in this case that the X Ray irradiation is behaving more like the spark in your H2/O2 mix than a lump of platinum.

[Karlos]

@Kenny

Did you do Nuclear/Radiochemistry in any of your degree options?

Isomeric implies the same components in a different configuration. This goes for for nuclear structure too (as distinct from isotopes of course).

[Karlos]

We all live and learn. If you studied radiochemistry I would expect you to have bumped into nuclear isomers before. It's part of the shell model IIRC - that is that the protons/neutrons are arranged in concentric shells, with different overall conformations possible (especially for open outer shells), but overall the system is fluid over a long timescale. Some combinations just aren't stable in any conformation (long term) once you get a large enough nucleus and so you begin to get your radioactive nuclei...

-edit-

Perhaps your prodigious intake of knowledge has caused some older, relatively unused information to be expunged :lol:

I use that excuse all the time :-D