ENERGY-LOSS AND RESONANT COHERENT EXCITATION OF FAST HIGHLY-CHARGED IONS ON A PT (110) SURFACE

Highly charged nitrogen ions at an energy of 21.8 and 23.0 MeV are sca ttered from a Pt (1 1 0) single crystal surface. Under surface channel ing conditions the charge state and the energy losses of the scattered ions are measured. For incident N6+ at 21.8 MeV resonant coherent exc itation (RCE) is observed. The ions are excited from Is to 2s, 2p by t he periodic potential of the Pt [1 (1) over bar 0] surface rows and he nce ionized owing to the larger orbitals of the 2s,2p states. The sign ature of the effect are N7+ ions observed at proper channeling conditi ons and at the resonant energy. The energy losses of the scattered ion s are in the range of 100 keV depending on the charge and the trajecto ries of the ions. (C) 1998 Elsevier Science B.V.