What is the source of light emitted from combustion reactions?

[Infrasound]

As a bit of a lay-person when it comes to physics...

When considering combustion reactions (example: wood burning), I am a bit unsure about the source of the light of the flame.

My current thoughts are the following:

Maybe:

1. The photons are produced from the exchange of an electron during the combination of carbon and oxygen atoms. Some transition takes place in which a photon is emitted.

Or

2. Energy from the combustion process causes collisions between other atoms/molecules, and due to the collisions, electrons reach a higher energy level, and then decay back, releasing a photon in the process. Wouldn't this be something like blackbody radiation?

Or

3. Maybe a combination of both of the processes?

Any help is greatly appreciated. Hopefully someone can steer me in the right direction. Thanks in advance.

 

[Feldoh]

I think that what you are describing in 1 and 2 are the same thing. The atoms collide and start to give off heat. The vibrations (heat) then gives off light as the result of things jumping between energy levels.

 

[alxm]

Yes, it's both. Note that it's not just electronic states that are discrete and can change by emitting/absorbing radiation. It applies to the vibrational and rotational states of the molecules as well.

The red glow of embers is blackbody radiation. The flame color is due to electronic transitions/ionization in the burning gas, which is why it's specific to the substance that's burning.

 

[Infrasound]

Thank you very much.