A CLASSICAL AND SEMICLASSICAL STUDY OF ELECTRON-ATOM COLLISIONS IN THE PRESENCE OF MONOCHROMATIC AND BICHROMATIC LOW-FREQUENCY LASER FIELDS

Laser-assisted electron-atom collisions are studied using classical me chanics and short- and long-ranged model potentials for the electron-a tom interaction. The classical energy transfer is compared with the va lues predicted by the soft-photon approximation and the differences ar e related to an adiabaticity parameter, which indicates the ratio of t he time scales involved. Radiation of arbitrary polarization and the c ase of the combination of a laser fundamental and its first or second harmonic are also considered.