Distorted-wave theory of heavy-particle collisions at intermediate energies

The quantum-mechanical description of heavy-particle collisions is extended to the intermediate-energy range through the use of a second-order distorted-wave approximation. Cross sections are calculated using close-coupled solutions for low partial waves and first- and second-order unitarized distorted-wave solutions for higher partial waves where the distorted-wave method is accurate. The method is applied to the calculation of charge transfer cross sections for collisions of ${\mathrm{C}}^{3+}$ with H, and of ${\mathrm{O}}^{2+}$ with He over the energy range 0—5 keV/amu, and to investigate the influence of the charge transfer channel on ion-impact excitation of ${\mathrm{O}}^{+}$.