Low-pressure DC breakdown in alcohol vapours

The results covered in this paper provide breakdown data represented by Paschen curves for methanol, isopropanol and n-butanol, along with the corresponding axial profiles of emission in Townsend regime of the discharge and including the optical emission spectra. Paschen curves were recorded in the range of pd (pressure x electrode gap) from 0.10 to 3.00 Torr cm. The optical emission spectra (OES) are recorded for wavelength range from 300 to 900 nm, for discharges in all studied alcohols. The recorded spectra enabled identification of species that participate in these discharges. All three alcohols exhibit emission from excited radicals OH (at 306.4 nm), CH (at 431.2 nm) and H α (at 656.4 nm) produced mostly in dissociative excitation by electrons. Recorded profiles of emission enabled us to identify conditions where processes induced by heavy particles (ions and fast neutrals) are dominant in inducing emission from the discharge. Graphical abstract