# Photon Absorption

1. May 30, 2008

### nothing123

Quick question: when an electron absorbs a photon with MORE THAN enough energy to jump one energy level but not two, what happens to the extra energy the electron doesn't absorb?

Thanks.

2. May 30, 2008

### Dick

If there's no state for it to jump to by absorbing the whole photon, it can't absorb the photon.

3. May 30, 2008

### AstroRoyale

The probability, or cross sections for photon absorption for bond levels in atoms are extremely peaked at the frequency of the transition, $$h\nu = E_u - E_l$$, pretty much like delta functions. Well, they're actually Lorenzian profiles, but the width is extremely small, ~$$10^{-4} \AA$$ for most transitions. If the photon doesn't have essentially the same energy as the energy difference of the levels, it won't get absorbed.