Electron emission by Doppler-mediated formation of doubly excited in grazing incidence of protons on clean

¹ J. Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech Republic - Dolejskova 3, 18223 Praha, Czech Republic
² Institute of Radio Engineering and Electronics, Academy of Sciences of the Czech Republic - Chaberská 57, 18251 Praha, Czech Republic
³ Institut für Allgemeine Physik, TU Wien Wiedner Hauptstrasse 8-10, A-1040 Wien, Austria

Received: 13 November 2000
Accepted: 16 March 2001

Abstract

We present a new electron emission process which may give rise to a structure in electron energy distributions observed for grazing incidence of protons on atomically clean . It is conjectured that the formation of doubly excited negative hydrogen ions from the Doppler-shifted surface-density-of-states results in autodetached electrons which are scattered and diffracted at the monocrystalline surface. This scenario is a modification of a recently suggested model which assumed electron production from elastic collisions of projectiles with the free-electron gas at the surface and diffraction upon escape into vacuum. The here proposed process should be most significant for hydrogen projectiles with comparably low energy (< 10 ).