Experiments on electron-impact ionization of atomic and molecular ions

Recent experimental measurements of cross sections for electron-impact ionization of atomic and molecular ions will be highlighted, with emphasis on results obtained with the crossed-beams method. These accurate absolute cross sections and high-resolution energy scans for atomic ions provide valuable benchmarks for theoretical efforts on direct and indirect ionization of these ions. Experimental data on ionization of molecular ions should motivate more theoretical interest in these more complex systems.