[en] Experimental data on energy, spatial and charge distributions of light ions and atoms leaving solid surface under irradiation are generalized for the first time. Theoretical models of light ion reflection from polycrystalline solid bodies and models of charge fraction formation are presented. Methods for practical application of light ion scattering for analysis and diagnostics as well as problems of particle reflection and energy under interaction of hydrogen and helium isotopes with walls of thermonuclear facilities of different types are considered