Absolute differential cross sections for small-angleHe+-He elastic and charge-transfer scattering at keV energies

This paper reports measurements of absolute differential cross sections for elastic and for charge-transfer scattering in ${\mathrm{He}}^{+}$-He collisions. Elastic-scattering cross sections have been determined at 1.5 keV over the laboratory angular range 0.04°–1.0° while charge-transfer cross sections have been determined at 1.5, 2.5, and 5.0 keV over the range 0.02°–1.0°, and at 0.25 and 0.50 keV over the range 0.02°–7.8°. The experimental data exhibit strong oscillations over the range of angles and energies studied and are in agreement with partial-wave theory calculations using phase shifts derived from proposed forms of the gerade and ungerade ${\mathrm{He}}_2^{+}$ interaction potentials. The experimental cross sections have also been integrated over angle to provide absolute integral cross sections.