Protonium formation in slow collisions of antiprotons with hydrogen atoms

Protonium formation + H → p + e is investigated theoretically at centre-of-mass collision energies less than E = 10 eV. In previous studies on the break-up ionization + H → + p + e, the present author introduced the direct numerical method using a discrete-variable-representation technique to solve the time-dependent (semiclassical) Schrodinger equation. The same method is applied to protonium formation. The reliability of the adiabatic molecular picture is examined for the calculation of the formation cross section. At very low energies, the centrifugal barrier plays an important role in the protonium formation as found in a variety of ion-molecule chemical reactions.