INFLUENCE OF THE COULOMB REPULSION BETWEEN ELECTRONS ON THEIR ENERGY-SPECTRUM IN THE CASE OF THE NONLINEAR SURFACE PHOTOEFFECT

It is shown that the Coulomb interaction among electrons that is produced by the laser-induced surface multi-photon photoeffect may change the initial energy spectrum of the electrons dramatically. The expansion of a photoelectron bunch (during transit from the surface to a detector) results in an increase of the electron energy and a broadening of the energy spectrum. The theoretical estimates of this effect are in good agreement with experimental energy spectra [Phys. Rev. A 41, 4123 (1990)]. The unexpectedly high energy of the electrons can be explained by the Coulomb interaction between the electrons.