Self-consistent microscopic theory for non-linear optical response of ultrathin metal films

In this paper self-consistent microscopic theory of nonlincar-optical response in ultrathin (similar to 1 nm) metal films has been developed. The single-electron wave functions, charge and current densities and field distribution in and out of film has analytically calculated in second approximation of perturbation theory. Electron wave functions calculated using density functional theory in time-dependent local density approximation. For ions a jellium model was used. Constructed theory describes second harmonic generation (SHG) from both of quantum well transitions and collective electron excitations.