Bremsstrahlung radiation emitted in fast-electron–H-atom collisions

A previous calculation for free-free transitions is generalized so as to treat one-photon (spontaneous) bremsstrahlung emitted in the course of collisions of relatively fast electrons with atomic hydrogen. While the electron-atom collision is described within the first Born approximation, the role of the atomic spectrum is taken into account exactly via the use of a compact representation of the Coulomb Green’s function. We discuss the main features of the cross sections and address some physically relevant issues such as the importance of the screening by the atomic electron, the role of the atomic structure, and limiting cases such as the soft-photon and the small-momentum transfer limits. We also discuss the differences observed between the cross sections for spontaneous bremsstrahlung and stimulated free-free transitions.