Molecular-state treatment of excitation and charge-transfer processes inH++He(1s2) collisions

The molecular-state expansion method within the impact-parameter formalism is applied to the processes ${\mathrm{H}}^{+}$+He(1$s^2$) →H(nl)+${\mathrm{He}}^{+}$(1s) and ${\mathrm{H}}^{+}$+He(1$s^2$) →${\mathrm{H}}^{+}$+He(1s,2l). Electron translation factors are incorporated into the scattering wave function, so that the cross sections obtained are free from the origin dependency. It is shown that stepwise flux promotion is the primary mechanism for excitation and electron capture into excited states at lower energies, and hence it is necessary to include all these channels in the close-coupling method to achieve reliable results.