Differential Scattering of Li+ Ions by He, N2, and O2 in the Range 3-400 eV

Abstract

Absolute elastic differential cross sections have been measured for ${\mathrm{Li}}^{+}$ on He, ${\mathrm{N}}_2$, and ${\mathrm{O}}_2$. In the center-of-mass system the collision energies range from 3.6 to 328 eV and the scattering angles from 1° to as high as 90°. An energy analysis was performed on the scattered ${\mathrm{Li}}^{+}$ ion beam. The inelastic cross section for ${\mathrm{Li}}^{+}$ + He was less than 2×${10}^{-19\mathrm{}}$ ${\mathrm{cm}}^2$ ${\mathrm{sr}}^{-1\mathrm{}}$ for all values of $E\theta$ measured up to 6000 eV deg. The analysis of the inelastic scattering of ${\mathrm{Li}}^{+}$+${\mathrm{N}}_2$ and ${\mathrm{Li}}^{+}$+${\mathrm{O}}_2$ shows some structure representative of the target molecule and indicates that inelastic scattering becomes the dominant process for $E\theta >4500\mathrm{}$ eV deg. The ${\mathrm{Li}}^{+}$+He elastic cross sections are smooth and relatively structureless. Lack of any rainbow angle structure indicates that the attractive well depth of Li${\mathrm{He}}^{+}$ is less than 0.2 eV.