Über die Temperaturabhängigkeit optischer Eigenschaften kleiner Silberteilchen
The influence of low temperature on the spectral light absorption of small silver particles has been investigated in the spectral range between 3500 and 4500 Å. Measurements of the absorption coefficient were taken at 293, 77, and 4.2 K.For this purpose a method was developed to obtain silver particles (mean diameter between 20 and 300 Å) inside a matrix of polymethylmethacrylate. This highpolymer allowed measurements of optical transmission at low temperatures and the exact determination of form and size distribution of the inbedded particles by electron microscopy. Using the Kramers-Kronig-analysis modified by Kreibig the optical constants were obtained. The results show relatively good agreement with constants calculated for the Drude free electron gas taking into account temperature dependend electron collision frequency.