Quantized vs. Continuous Energy Levels

Most recent answer: 09/16/2008

Q:
One thing I have never understood is that atomic particles are quantized in their allowed energy values e.g only allowed to have certain energy values e.g. electrons and spin but photons have a completely continuous energy spectrum. Is this because force exchanging particles (the photon is the force exchanging particle for the em force) are allowed any value. Or is there some theory that says these are also quantised in terms of energy level.
- Peter Rowan (age 58)
bath, UK
A:
Nice question. The distinction here is just that the 'atomic particles' are in bound states, not free to run around separately. If you also consider the energy of the overall motion of the atom, it's completely continuous too. So are the energies if the particles get enough energy to unbind.  Likewise if you put photons in a box, they also acquire a discrete energy spectrum

Mike W.

(published on 09/16/2008)