The energy loss of energetic ions moving near a solid surface

A systematic study of the energy loss by energetic ions moving near a solid surface has been made. Special emphasis is placed on the case of an ion moving with velocity less than that of electrons in the solid. A clear distinction is made between contributions to energy loss from the excitation of collective states and particle-hole pairs. At large distances from the surface the authors show that the contribution of collective excitation always dominates that from particle-hole excitation.