Energy Distribution, Drift Velocity, and Temperature of Slow Electrons in Helium and Argon

The energy distribution, and the drift velocity and electron temperature which are closely dependent on the distribution, were calculated for slow electrons in He and A under fields ranging from $\frac{X}{p}=1\mathrm{} \mathrm{to} 4$ volts/cm mm. The calculations were based on the theory developed by Holstein. The diffusion cross sections of the gases for electrons which account for the effect of elastic collisions were computed from the scattering data of Ramsauer and Kollath and of Normand. The effect of excitation collisions was taken into account by comparing the results for three representative values of excitation cross section: $Q_{\mathrm{ex}}=0\mathrm{}$ and $Q_{\mathrm{ex}}=\infty$ which form the limiting boundaries and $Q_{\mathrm{ex}}=\mathrm{a}\mathrm{constant}$ obtained from Maier-Leibnitz. Although a considerable percentage of the electrons were to be found in the excitation region for $Q_{\mathrm{ex}}=0\mathrm{}$, the results for $Q_{\mathrm{ex}}=\mathrm{constant}$ were nearly the same as those for $Q_{\mathrm{ex}}=\infty$. In the case of small fields, therefore, the electron energy distribution in the elastic region and related quantities may be calculated with $Q_{\mathrm{ex}}$ assumed infinite.