Abstract
We have investigated the effect of submonolayer molecular adsorptions on the surface-plasmon spectrum of silver and aluminum surfaces using low-energy electron-loss spectroscopy. Plasmon energy shifts of about 200 and 500 meV for one-monolayer hydrocarbon coverage were observed on silver and aluminum films, respectively. In addition, a new loss peak appears upon adsorption, which we associate with a molecular electronic resonance. Its energy shifts with increasing coverage in the opposite direction to that of the plasmon. A classical dielectric model is presented in which the losses are attributed to two branches of a collective excitation in a system consisting of (adsorbate) oscillators on top of a semi-infinite metal surface.
Original language | English |
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Pages (from-to) | 1006-1012 |
Number of pages | 7 |
Journal | Physical Review B |
Volume | 39 |
Issue number | 2 |
DOIs | |
State | Published - 1989 |