Absolute differential cross sections for small-angle H⁺-He direct and charge-transfer scattering at keV energies

L. K. Johnson, R. S. Gao, R. G. Dixson, K. A. Smith, N. F. Lane, R. F. Stebbings, and M. Kimura

Phys. Rev. A 40, 3626 (1989)

This paper reports measurements and calculations of absolute differential cross sections for H⁺-He charge-transfer and direct scattering. Charge-transfer measurements have been obtained at 5.0 keV laboratory energy over the laboratory angular range 0.02°­1.0°, while direct scattering has been observed at 0.5, 1.5, and 5.0 keV laboratory energy over a closely corresponding angular range. Calculations are reported for 0.5, 1.5, and 5.0 keV charge-transfer and direct scattering. The measured cross sections are in good agreement with those derived from fully quantum-mechanical molecular-orbital close-coupling calculations. Direct scattering cross sections are also found to be in agreement with single-potential calculations using directly summed Jeffreys-Wentzel-Kramers-Brillouin phase shifts derived from proposed H⁺-He ground-state interaction potentials. The cross sections exhibit significant structure over the range of angles and energies studied. The measured cross sections have been integrated over the experimental angular range providing absolute integral cross sections for comparison with theoretical results and previously measured total cross sections.