To confirm the appropriateness of ideas recently put forward [L. F. Er
rea, C. Harel, H. Jouin, L. Mendez, B. Pens, and A. Riera, Phys. Rev.
A 52, R2505 (1995)] concerning the validity of the molecular approach
to calculate ionization cross sections, we treat the H+ + H- reaction
as a widely different benchmark.