The convergence of the close-coupling formalism is studied by expanding the target states in an orthogonal L Laguerre basis. The theory is without approximation, and convergence is established by simply increasing the basis size. We present convergent elastic, 2s, and 2p differential cross sections, spin asymmetries, and angular-correlation parameters for the 2p excitation at 35, 54.4, and 100 eV. Integrated and total cross sections as well as T-matrix elements for the first five partial waves are also given.

The substantial progress that has occurred during the 1990s in the field of electron-atom-collision theory is discussed. We show how a solution of a small-model three-body problem, using the convergent close-coupling method, has led to numerous applications involving real atomic collision systems. Consequently many fundamental electron-atom collision processes are considered as `solved', and accurate collision data of interest to science and industry have become available. However, we suggest that the present has only just seen the birth of modern atomic collision theory. There are many more important collision problems to be tackled, with guidance coming from experiment being as important as ever.

A computationally efficient analytic form of the Born-approximation electron-impact ionization amplitude is derived for general neutral-atom targets. High-quality Hartree-Fock Slater orbitals are used to model the target wave function. Full orthogonalization of the continuum Coulomb wave to all occupied orbitals of the target atom is enforced. Results are presented for noble gases ͑Ne, Ar, Kr, and Xe͒, selected transition metals ͑Fe, Cu, and Ag͒, and elements from the fourth, fifth, and sixth columns of the periodic table ͑Si, Ge, Sn, P, As, Sb, S, Se, and Te͒, where theoretical comparisons are lacking. Full orthogonalization significantly improves agreement with experimental data for the noble-gas series compared to previous Born models. Overall agreement with all elements is uniformly good and variations within each series are systematic.

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We present the total ionization cross section and spin asymmetry at projectile energies ranging from threshold to 500 eV for electron-impact excitation of atomic hydrogen. They are calculated using the convergent close-coupling formalism of Bray and Stelbovics [Phys. Rev. A 46, 6995 (1992)]. Both observables are found to be in complete quantitative agreement with measurements over almost the entire energy range. This is the only electron-atom scattering theory that is able to achieve this result to date. [13,14], and that pseudoresonances are simply an indication of an inadequate representation of the target. In the latter paper we applied the CCC method to the full e-H scattering problem in order to 746