Differential and integrated cross sections for the elastic process H^+ + H(1s) → H^+ + H(1s) were calculated with the use of results of coupled-state calculations in the energy range 15-200 keV. Results are presented and, at 60 keV, compared favorably with preliminary experimental data. The asymptotic form of the elastic amplitude for b≫a_0 (where b is the impact parameter) is derived for the two cases λ≪1 and λ≫1, where λ is the ratio of the collision duration to the orbital period. The asymptotic form for λ≫1 provides a useful test on the numerical accuracy of the amplitudes.
Wadehra JM, Shakeshaft R. Elastic scattering of protons from hydrogen atoms at energies 15-200 keV. Phys. Rev. A. 1982;26(3):1771-1774. doi: 10.1103/PhysRevA.26.1771