LASER-ASSISTED ELASTIC ELECTRON-ATOM COLLISIONS

We report experimental measurements of electron spectra resulting from the scattering of 9.5-eV electrons by helium atoms through an angle o f 9-degrees in the presence of a high-intensity (approximately 10(8) W cm-2) CO2 laser. The intensities of the additional peaks which occur separated from the elastic scattering peak by multiples of the photon energy in the presence of the laser are much greater than expected. Th ese data suggest that calculations based on the Kroll-Watson approxima tion, usually applied to this type of experiment, are inappropriate fo r these scattering conditions.