Study of electron transport in hydrocarbon gases

Abstract

The drift velocity and the effective ionization coefficient of electrons in the organic gases, C2H2, C2H4, C2H6, CH3OH, C2H5OH, C6H6, and C6H5CH3, have been measured over relatively wide ranges of density-reduced electric fields (E/N) at room temperature (around 300 K). The drift velocity was measured, based on the arrival-time spectra of electrons by using a double-shutter drift tube over the E/N range from 300 to 2800 Td, and the effective ionization coefficient (α − η) was determined by the steady-state Townsend method from 150 to 3000 Td. Whenever possible, these parameters were compared with those available in the literature. It has been shown that the swarm parameters for these gases have specific tendencies, depending on their molecular configurations.

Expression of longitudinal third-order transport coefficient in terms of α parameters and its validity

“…Kondo and Tagashira [6] introduced new electron transport coefficients called α parameters, which are defined by arrival-time spectra of an electron swarm, and reported that the α parameters are related to D 3L . Arrival-time spectra of an electron swarm can be measured by a double-shutter drift tube, and the procedure for obtaining the α parameters from the measured arrival time spectra is well established [7][8][9][10][11][12][13][14][15]; therefore, there is a possibility that values of D 3L are obtained experimentally by the α parameters.…”

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

“…In case of ethanol vapour, our results agree well with those of Hasegawa's and Date's for the E/N range of 1.5-3 kTd. Furthermore, results from Hasegawa [46] and Raether [48] (as presented by von Engel in [49]), in the overlapping range of E/N (140-700 Td), differ from each other (Fig. 3b) by a large factor, even greater than 3, the effective ionization coefficients from Raether [48] being much smaller.…”

“…Hasegawa's and Date's results for methanol [46] cover the region of much lower values of the reduced electric fields, from 130 Td to 3 kTd. For the overlapping range of E/N , our effective ionization coefficients in methanol vapor are slightly lower than those in the work of Hasegawa and Date (Fig.…”

“…Figure 3 shows dependence of the effective ionization coefficients α eff /N on reduced electric field E/N for the discharges in methanol, ethanol, isopropanol, and n-butanol vapours, obtained in the range of E/N from 1 kTd to 8.8 kTd. For comparison we also show results for effective ionization coefficients from the literature that are available only for methanol and ethanol [46,47] and [48] as compiled in [49]. Additionally, we give numerical data listed in Table 1 that correspond to the results shown in Fig.…”

“…3a). The difference [46] (solid black triangles) and Shlumbohm [47] (black X) and with data for ethanol from Hasegawa and Date [46] (open black triangles) and von Engel [49] (black X). Additionally, c) shows the results obtained from our experiment for isopropanol and n-butanol presented together with the results for methanol and ethanol increases to almost a factor of two above 2 kTd.…”