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[en] The diffusion coefficient for thermal electrons in mercury vapour has been measured using the Cavalleri electron density sampling technique. The result indicates that the average momentum transfer cross section for electrons is approx. 27x10^-16cm², a result which favours previously derived cross sections from drift velocity data over recent theoretical calculations

[en] The total (He⁺, He) and Ar⁺, Ar) charge-exchange cross sections have been measured in the energy range 1 keV < Esub(lab) < 10 keV, using the condenser-plate method. Special emphasis was placed on accurately controlling and measuring the target gas pressure, and this resulted in an uncertainty of less than 0.5% in the relative values of the cross section and 2.5% in their absolute values. The measured cross sections fit the expression (sigma)sup(1/2) = k₁ - k₂ 1n upsilon to within the experimental errors, and no oscillatory behaviour was observed. The cross section for (He⁺, He) has been calculated in the JWKB approximation, using published ²Σ⁺sub(g) and ²Σ⁺sub(u) potential curves. The calculated and experimental values agree within 10%. The experimental data have been analysed in order to obtain the cross section for electron loss in neutral (Ar, Ar) collisions, and this cross section was found to increase monotonically from (0.39 +- 10%) x 10^-16 cm² at 1.5 keV to (2.47 +- 10%) x 10^-16 cm² at 10 keV. (author)

[en] The Cavalleri electron density sampling technique has been used to measure the diffusion and attachment rate coefficients for thermal electrons in O₂, and in O₂-N₂ and O₂-CO₂ mixtures. The observed pressure dependence of the three-body attachment rate coefficient is shown to be caused by the selective removal of electrons from the distribution at the attachment resonance energy, and the magnitude of this effect ('attachment cooling') is shown to be a measure of the magnitude of the rotational excitation cross sections in O₂ and N₂. Three-body rate coefficients for the formation of O₂^- involving O₂, N₂ and CO₂ as third bodies have been found to be 2.2, 0.11 and 3.5x10^-30cm⁶s^-1 respectively. The value of the diffusion coefficient for thermal electrons in O₂ is found to be (37+-3)x10²¹cm^-1s^-1

[en] The drift velocities of electrons in dry CO₂-free air at 293 K have been measured over the range 0.1<=E/N<=1 Td for gas pressures between 0.4 and 1.3 kPa

[en] Values of μN for thermal electrons in carbon dioxide have been derived from measurements of the diffusion coefficient over the temperature range 296-468K. The present values are in agreement with those reported by Haddad and Elford