Temporary negative ion formation in interactions of low-energy inert gas ions (He +, Ne +) with Cs-adsorbed Cu(111) surfaces

• Published in: Surface science Vol. 341; no. 1; pp. 19 - 28
• Main Authors: Lu, Q.B., O'Connor, D.J., King, B.V., Shen, Y.G., MacDonald, R.J.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.11.1995; Amsterdam Elsevier Science; New York, NY
• Subjects: Adatoms; Alkali metals; Applied sciences; Atomic, molecular, and ion beam impact and interactions with surfaces; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron and ion emission by liquids and solids; impact phenomena; Electron emission; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Impact phenomena (including electron spectra and sputtering); Ion-solid interactions, scattering, channeling; Metals. Metallurgy; Physics; Surface and interface electron states; Surface electronic phenomena; Surface states, band structure, electron density of states; Adatoms; Ion-solid interactions, scattering, channeling; Electron emission; Alkali metals; Surface electronic phenomena; Particle surface interaction; Adsorption; Transition elements; Physical radiation effects; Electron spectra; Cesium; Copper; Experimental study; Surface states; Ion beams
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/0039-6028(95)00725-3

Low-energy (0.5-1 keV) inert gas ions (He +, Ne +) have been used to investigate the interaction of ions with Cs-covered Cu(111) surfaces. Electron spectra from the interaction were obtained for grazing angles of incidence. From the energy and angular distributions of emitted electrons, it can be confirmed that the sharp electron peaks with excitation energies of 19.32±0.08 and 16.15±0.08 eV are caused by the decays of He∗ −(1s2s 2 2S) and Ne∗ −(2p 53s 2 2P) states, respectively. It was also found that negative ion resonances take place on the incoming trajectories far above the surface ion cores. The one-step two-electron capture has been proposed to explain the formation of negative-ion resonances.