Electron-capture cross sections for high-energy alpha-particle-helium-atom collisions

The continuum distorted-wave (CDW) approximation has been used to calculate electron-capture cross sections Q(nl) when fast alpha particles collide with a helium target atom. Of prime interest is the sensitivity of each Q(nl) with respect to improvements in the target wavefunction up to and beyond the Hartree-Fock level, the final description being provided by a 99% correlated wavefunction. Trends are contrasted with the example of proton projectiles. Total capture cross sections are reported and compared with experiment.