Total Cross Sections for Inelastic Scattering of Charged Particles by Atoms and Molecules. IV. Positive Lithium Ion

Abstract

The Born cross sections for several important discrete excitations of ${\mathrm{Li}}^{+}$ from its ground state have been calculated with correlated wave functions. By extrapolation, cross sections for higher excitations have also been determined. Subtraction of the sum ${\sigma }_{\mathrm{ex}}$ of these excitation cross sections from the total inelastic-scattering cross section ${\sigma }_{\mathrm{tot}}$ obtained through a sum rule for the Bethe cross sections yields a reliable "counting" ionization cross section ${\sigma }_i$. The cross sections thus obtained are ${\sigma }_{\mathrm{tot}}={\left(\frac{z}{\beta }\right)}^2\left(0.536\right\{\ln \left[\frac{{\beta }^2}{(1-{\beta }^2)}\right]-{\beta }^2\}+5.216\mathrm{}\pm 0.002)\times {10}^{-20\mathrm{}}$ ${\sigma }_{\mathrm{ex}}={\left(\frac{z}{\beta }\right)}^2\left(0.265\right\{\ln \left[\frac{{\beta }^2}{(1-{\beta }^2)}\right]-{\beta }^2\}+2.295\mathrm{}\pm 0.002)\times {10}^{-20\mathrm{}}$ and ${\sigma }_i={\left(\frac{z}{\beta }\right)}^2\left(0.271\right\{\ln \left[\frac{{\beta }^2}{(1-{\beta }^2)}\right]-{\beta }^2\}+2.921\mathrm{}\pm 0.004)\times {10}^{-20\mathrm{}}$ where $\mathrm{ze}$ is the charge of the incident particle and $\beta$ is its velocity divided by that of light. The ionization cross section is in excellent agreement with experimental data in the asymptotic region (incident electron energy ≳ 5 keV).