Electron impact ionization of Rydberg atom

Collision between electron and Rydberg atom is important in ultracold plasmas, frozen Rydberg gases and formation of antihydrogen in a Penning trap. In superelastic scattering the electron gains the energy released by quenching the Rydberg atom. This is the most likely mechanism proposed to explain the heating of electrons observed in recent ultracold plasma experiments. Impact ionization and three-body capture are the two basic processes and the balance between the corresponding rates is essential in recombination in a cold plasma. Quantal calculations, initial angular momentum dependencies, scaling laws and correspondences to classical trajectory Monte Carlo simulations are presented and discussed.