Excitation of an electron by a photon

[nokia8650]

Hi, I had a question regarding excitation. If a photon is absorbed by an electron, and some of the energy is gained by the electron, which then moves to a higher energy level, what happens to the rest of the photon's energy - is a photon of lower energy, corresponding to the difference in energy gained by the electron and energy of photon emitted?

For example, in the case of a hydrogen atom, the ground state is -13.6eV, the second energy level -3.4eV, and the third -1.5eV.

If a photon of 11.5eV collides with an orbiting electron in the ground state, the electron will use 10.2eV of this, and be promoted to energy level 2; it however doesn't have enough energy to get to energy level 3. Is a photon, therefore of energy 11.5-10.2= 1.3eV emitted?

Thanks for any help.

 

[Dick]

Yes. You can also think of it as an elastic collision which changes the energy of the incoming photon.

 

[nokia8650]

Thanks for clearing that up.