Anregung durch Licht und Eigenschaften der Volumen- und Oberflächen-Plasmaschwingungen in dünnen Schichten des Alkalimetalles Rubidium

Abstract

Optical transmission, reflexion and absorption of thin films of the alkali metal rubidium were measured as a function of thickness for ∥ and ⊥ polarised monochromatic radiations having wavelenghts between 3000 and 6000 Å, incident from the vacuum side as well as from the quartz-support side at angles of 45 ° and 30 ° resp. The films were prepared by evaporation in static ultrahigh vacuum (∼ 10⁻¹⁰ Torr) onto a cooled (90 °K) smooth surface of a thin, plane-parallel plate of polycrystalline quartz. The thickness of the slowly condensing films was varied continuously from zero to some thousand Angström-units corresponding to the bulk metal.

The results obtained permit the identification of the volume- or the surface-character of the different plasma oscillations and, in the latter case, the surface they are attached to, the determination of their resonance frequency and a quantitative analysis of their developement with increasing film thickness.