Autoionization and autodetachment in collisions of slow inert gas ions with partially K covered W(110) surfaces

Abstract

We report the spectra of the electrons emitted after slow collisions (50 to 1000 eV) of inert gas ions (He +, Ar +, Xe +) with partially K covered W(110) surfaces. At collision energies below 250 eV autodetachment of the excited negative ion states X −∗ (He −∗(1s2s 2), Ar −∗(3p 54s 2), Xe −∗(5p 56s 2)), formed by resonant two-step capture of two surface electrons, is collisions the formation of the He −∗ resonance could be confirmed by model calculations which simulate the electron spectra. At higher energies in addition the autoionization of Ar ∗∗(3p 44s 2) and K ∗∗(3p 54s 2) is detected. These states are formed via promotion in inert gas ion collisions with the surface adsorbed K atoms. Besides these intra-atomic Auger processes also interatomic Auger processes involving one or two electrons of the surface (Auger de-excitation and Auger capture) are observed.