Ionization amplitudes in electron-hydrogen collisions

Recently Zatsarinny and Bartschat [Phys. Rev. Lett. 107, 023203 (2011)PRLTAO0031-900710.1103/PhysRevLett.107.023203] have given an ansatz for extracting ionization amplitudes from close-coupling calculations of electron-impact ionization of atoms. They applied it with extraordinary success to a fully differential cross section of electron-helium single ionization leaving the residual ion in an n=2 state. By considering electron-impact ionization of atomic hydrogen we explain the origin of the ansatz and show that it forms an effective interpolation scheme for determining the amplitudes, so long as the pseudostate energy distribution is sufficiently dense. © 2014 American Physical Society.