What I want to do
There seem to be some distinct lines missing in the Chalmette flare spectra folks have been collecting. There's a separate post on emission spectra in these, which is the primary goal; this is more of a speculative exploration on if we can also measure absorption lines since the flame is a good full-spectrum light source and the steamy/smoky stuff coming out might allow us to detect some molecules. Emission spectra are mostly just for atoms, not full molecules, so this would be a nice secondary technique.
Here's a great example of an atmospheric spectrum (of the sky):
My attempt and results
Since we're not sure Scott's spectrometer is well calibrated, I tried to align the spectra visually using the green band as a reference. I compared it to another spectrum from a Desktop kit, so the scale should be similar.
It seems to me that the faint line in the flare spectrum aligns with the ~760nm O2 line in the sky spectrum. Since that's a particularly strong absorption line (see this annotated one by Liz), that seems feasible.
Questions and next steps
If we can identify some other absorption lines, and clean up the data a bit, we might be able to fingerprint other whole molecules.
We should also try to figure out what the big missing region (big dip) in the red part of the spectrum is -- I don't think any absorption lines are that wide, so what's going on there (below)?