Effective ionization coefficients for low current dc discharges in alcohol vapours at low pressure

Abstract

This paper presents results for effective ionisation coefficients ($$\alpha _{\mathrm {eff}}/N$$ α eff / N , N—gas density) obtained from the breakdown voltage and emission profile measurements in low-pressure dc discharges in vapours of alcohols: methanol, ethanol, isopropanol, and n-butanol. Our results for $$\alpha _{\mathrm {eff}}/N$$ α eff / N are determined from the axial emission profiles in low-current Townsend discharge and lay in the interval of reduced electric field E/N (E—electric field, N—gas density), from 1 kTd to 8.8 kTd. We also give a comparison of our experimental results with those from the available literature. Our data cover the high E/N range of the standard operating conditions and in the region where other data are available we have a good agreement. Graphic abstract

Electron Swarm Parameters of Alcohols from Electron Collision Cross–Sections

“…For the reduced ionization coefficient, we have experimental values reported in the literature for all the studied alcohols with E/N values from 130 Td and with a maximum of 8800 Td [37,[40][41][42]. There is a good agreement in the profile of the obtained data presented in Figure 6 for methanol and ethanol which have a better-defined cross-section set in the range where the calculations were performed.…”

“…Reduced ionization coefficient for (a) Methanol, (b) Ethanol, (c) Propanol, (d) Butanol as a function of E/N. (solid lines from BOLSIG+ (B+), and solid line-point from METHES (MT), subscript (T) theoretical and (X) experimental data set cross-section, solid circles experimental data from Hasegawa and Date[37], Marjanović et al[40], Schlumbohm and Angew[41] and Engel[42]…”

Electron swarm parameters of alcohols from electron collision cross–sections

“…where D L is the longitudinal diffusion coefficient, ν ef f is the effective ionization frequency (equal to ionization frequency minus attachment frequency), and W is the bulk drift velocity, which gives the velocity of the center-of-mass of the electron cloud, parameters already obtained and demonstrated [42]. There are experimental values of α reported in the literature for all the studied alcohols with E/N values from 130 Td to 8800 Td [39,[43][44][45]. Figure 6 collects them and the obtained data.…”

Science-based, data-driven developments in plasma processing for material synthesis and device-integration technologies

“…92) Further investigation showed that the effective ionization coefficients for the alcohol vapors were measured by breakdown voltage and emission profile measurements in low-pressure DC discharges. 93) Electron collision cross-sections of dimethyl ether (DME, C 2 H 6 O) were measured under a constant electric field and crossed electric and magnetic fields through the standard swarm analysis. 94) A multiple term solution of the BE for electron noble gases, including He, Ne, Ar, Kr, and Xe, were discussed by considering the third-order transport coefficient tensor 95) and the effect of longitudinal field components on the spatial profile of electron swarms.…”