Electron emission from the interaction of He projectiles and UV photons with LiF on W(110)

Abstract

The electronic structure of thin LiF adlayers deposited on W(110) at room temperature is studied by ion impact electron spectroscopy (IIES) with He⁺ ions, metastable impact electron spectroscopy (MIES) with He∗ atoms, ultraviolet photoelectron spectroscopy (UPS), and to some extent with electron energy loss spectroscopy (EELS). The transition from the electronic structure of single adsorbed molecules to the emergence of the bulk structure could be studied by following the emergence of bulk properties, in particular the bandgap, as a function of the LiF exposure. The first step in the layer growth is molecular absorption of LiF. The next step is the formation of islands formed by the LiF molecules.

The production of vacancies in the 2p F orbital under the influence of the ionizing radiation is studied as a function of the LiF exposure. Their relevance for the desorption processes induced by electronic transitions (DIET) is discussed.

Key Words:

• LiF adlayers on W(110
• electronic structure
• IIES
• MIES
• UPS