# Gas and photons

1. Aug 24, 2014

If a gas is bombarded with light will the atoms absorb the light and emit photons of an equal energy level?

2. Aug 24, 2014

### mathman

It is more complicated and depends on the constituents of the gas. Typically when a photon is absorbed an atom or molecule will go to a higher energy state. What happens next depends on the material and the photon wavelength.

3. Aug 24, 2014

### ChrisVer

They don't have to emit photons of an equal energy level... I'm talking about photon absorption...
For a rough example, suppose you have three energy levels... $E_{3} > E_{2} >E_{1}$... if the absorbed photon has energy $E= |E_{3}- E_{1}|$, then you can have the production of 2 photons of energy $\epsilon_{a}=|E_{3}- E_{2}|$ and $\epsilon_{b}=|E_{2}-E_{1}|$...

4. Aug 24, 2014