Invariant embedding approach to secondary electron emission from metals

Based on an invariant embedding principle for the backscattering function we calculate electron emission yield metal surfaces at very low impact energies. Solving equation within a quasi-isotropic approximation and using effective mass model solid, experimental data are fairly well reproduced provided (i) incoherent scattering ion cores is allowed to contribute cascades inside solid (ii) transmission through surface potential takes into account Bragg gaps due coherent crystal planes parallel as randomization of electron's lateral momentum elastic defects. Our results suggest that in order get secondary electrons out metals, large energy loss inelastic electron-electron has be compensated by electron-ion core scattering, irrespective crystallinity sample.