Two- and one-center close-coupling calculations for ionization of atomic hydrogen by antiproton impact - art. no. 024701

Ionization of atomic hydrogen by antiproton impact is studied by a two-cent er atomic-orbital close-coupling method supplementing projectile orbitals t o the one-center expansion. Two-center effects are not negligible at interm ediate and low energies, though antiprotons do not have bound states of ele ctrons. The one-center expansion fails to represent the electron distributi on near the antiproton where the electron tends to be evacuated by the repu lsive interaction from the negatively charged nucleus. The integrated ioniz ation cross sections are less sensitive to the details of the electron dist ribution, but below 1 keV the one-center expansion underestimates the ioniz ation cross sections due to its inability to represent the expanding distri bution of ionized electrons.