Zur Abhängigkeit der optischen Eigenschaften des Natriums von Temperatur und Aggregatzustand im Wellenlängenbereich von 0,3 bis 2,5 Μm
The optical constants of the alkali metal sodium have been measured in the wavelength region from 0.3 to 2.5 Μm in the solid and liquid state at temperatures between 90 and 370 K, by analysing intensity and polarisation of the monochromatic radiations reflected by the surface of the metal. These mirrolike surfaces, free of contamination and not distorted by any treatment, were prepared and measured in ultrahigh vacuum. The purity of the metal was checked by measuring the residual resistance at liquid helium temperatures. The values thus obtained forn, k,ɛ1=n2-k2 andɛ2=2nk, listed in tables, and their temperature dependence permit to separate quantitatively the absorption due to different absorption mechanisms and to determine some of the quantities describing the behaviour of the free electrons.