Understanding Line Spectra: Evidence of Atomic Energy Levels

[Air]

Hello, can someone explain how a line spectrum works. How do they provide evidence of energy levels in atoms?

I would have thought that energy levels are to do with a different concept of Bands (Valence, Conduction) so how does a line spectrum provide evidence?

 

[Doc Al]

When atoms are isolated (as in a gas) things are quite different than when they are stuck together (as in the solid state). Here's a bit about the hydrogen spectrum (the simplest case) that might help you: http://hyperphysics.phy-astr.gsu.edu/hbase/hyde.html#c4"

 

[Air]

Thank you for the link.


This is what I am understanding:

Photons are associated with a particular energy and allow Electrons to change levels. Electrons are excited to higher levels (by emitting Photons) and when they fall back to lower levels, light is emitted. Different frequencies create different light and this makes up a line spectrum.

Is it correct?

 

[Doc Al]

I'd phrase it this way: When an electron falls from a higher energy level to a lower energy level, a photon is emitted whose frequency is proportional to the change in energy. The various energy levels and their differences determine the various photon frequencies, which form the "lines" of the spectrum (as opposed to a continuous spectrum).

 

[Gokul43201]

A good place to start: http://www.colorado.edu/physics/2000/quantumzone/bohr.html