Can reactions produce microwave or radio wave radiation?

I know that many reactions produce visible light, heat and sound, but is there a reaction (preferably one example for an inorganic and organic one) that could produce electromagnetic waves in the microwave and radio band?




An [ammonia maser](https://www.feynmanlectures.caltech.edu/III_09.html) qualifies as an inorganic RF-emitting reaction. As the nitrogen changes position in the $\ce{NH3}$ molecule, ~24 GHz radiation is emitted.


Similarly, organic methanol, $\ce{CH3OH}$ [makes a maser found in nature, emitting at ~36.2 GHz](https://phys.org/news/2017-08-astronomers-methanol-maser-emission-nearby.html) and also [at ~6.7 GHz](https://ui.adsabs.harvard.edu/abs/2014PASJ...66...31F/abstract).


BTW, if the reactants are moving away *rapidly* (e.g. interstellar gases), visible radiation is red-shifted to microwaves... or lower, so wavelength depends on your frame of reference. So, as Brumley and Stevens state, [listen in to radio astronomy](https://www.youtube.com/watch?v=xTPmCSu_55M).


Though these might be due to physical excitation, and not an exact answer for your question, an interesting experiment would be to form $\ce{NH3}$, e.g. with [the Haber process](https://en.wikipedia.org/wiki/Haber_process), and try to detect the 24 GHz radiation, perhaps due to initial formation of the molecule in a metastable state, or due to rearrangement. A similar experiment could be done with [methanol, forming it from $\ce{CO}$ and $\ce{H2}$](https://en.wikipedia.org/wiki/Methanol#From_synthesis_gas), looking for 36.2 GHz or 6.7GHz signals. I'd be *very* interested to know if you or anyone else tries that! 


 14