Der Zusammenhang zwischen dem magnetooptischen Kerr- und Faraday-Effekt und die optischen Konstanten von dicken Aufdampfschichten aus Eisen,Kobalt und Nickel

The magnetical rotation of the plane of polarisation and the ellipticity of the reflected and transmitted light through magnetically saturated, evaporated layers of iron, cobalt and nickel (30 to 100 mμ) are dependent one another according to the phenomenological theory of W.Voigt. The four measured magnetooptical angles are however independent each other. By comparison of other physical properties, except the magnetooptical ones, (f. e. magnetical saturation, optical absorption) measured respectively with transmitted and with reflected light, we try to prove, that the layers are homogenous at least near the glass-side. The linear increase of Faraday-rotation and optical absorption with the thickness of the layer supports this assumption. Then the independence can only be explaned by a magnetooptical term in the second equation of Maxwell also (precession of spin). The knowledge of the optical constants ist necessary for the comparison of magnetooptical ones. They are find out by measurements of intensity only, using the transmitted light and the reflected light at both sides of the layer. By supernumerarykinds of determination the foult is estimated. The method of Drude is adapted to measurements of intensity and then applied on the glasside too. The results on this side agree with those of transmitted light, the air-side differs a little.     

Optische Konstanten aufgedampfter Eisenschichten

Iron was heated and evaporated by electron bombardment. The condensation upon glass plates gives layers with highly reproducible thicknesses and optical constants. In the range of the visible spectrum, the constants were determined for opaque layers (thickness≧1000 Å) by the elliptical analysis of reflected light. They vary reproducibly with the conditions of preparation. The range of values covers most of the measurements published to date for iron. For oblique condensed layers the optical constants are very strongly anisotropic. Irreversible changes of the constants within the range of temperature from 150 to 400° C are presumably connected with crystalline growth.     

Optische Eigenschaften und Elektronenbandstruktur von Europium und Barium

Optical properties of the divalent rare earth metals europium and ytterbium, obtained by transmission and reflection measurements in the spectral range 0.3–4.0 eV at room temperature, demonstrate the close relationship between these two metals and the alkaline earth metals, especially barium. The structure occurring in the real part of the conductivityσ(ω) could be assigned to optical interband transitions by means of recent energy band calculations for europium. The similarity of the experimental absorption curves of europium and barium suggests, in the spectral range considered, an almost identical band structure of the two metals and, moreover, no effect of the 4f-electrons of europium in the optical spectrum exists.     

Derg-Faktor des 364 keV-Zustandes von184W und die Hyperfeinfelder von Wolfram in Eisen,Kobalt und Nickel

Theg-factor of the 364 keV state of¹⁸⁴W was measured by the time integral angular correlation method using the high hyperfine fields at the tungsten nucleus in iron. The same experiment was performed with the 111 keV state giving the ratiog(364 keV)/g(111 keV)=1.02(14). Using this ratiog(364 keV-level)=0.286(35) was deduced. For the hyperfine fields of W in Fe, W in Co and W in Ni at 300 K ?610(35) kG, ? 358(23) kG and ?80(3) kG respective have been determined.     

Diekll-Auger-Spektren von Eisen und Vanadium

The relative intensities of theKLL-Auger transitions of Fe (Z=26) und V (Z=23) were measured with an iron free, double focusing β-spectrometer. The results obtained are in good agreement with those measured bySokolowski andNordling forZ=29 andZ=32. This confirms the discrepancies between the nonrelativistically calculated intensities and the experimental values in the region of lowerZ. A summary is given about all known measurements of theKLL-Auger intensities. Also theKLL∶KLX-ratio of Fe was measured to be 1·0∶(0·19±0·01). The energy of the 14·4-keVγ-transition of Fe⁵⁷ was evaluated to be (14389±6) eV.     

Die optischen Konstanten des Kaliums und die Theorie von Drude

The results of new measurements of the optical constantsn andk of the alkali metal K, performed in ultrahigh vacuum on mirrorlike surfaces free of any contamination and distortion in the wavelength region from 0·365 μ to 2 μ at temperatures between ?183° C and +85° C were compared with the predictions of the Drude-theory. This permits the following main conclusions:

1. 1.
   The relation forn ²-k ²≡ε (real part of the metal's dielectric constant) derived by Drude proves to be valid; therefore, the total polarisation 4πNα (α=polarizability) of the metal remains small compared with 1 and the interband absorption has no influence on it.     
   
   

Optische Absorption und Fluoreszenz von NH 2 − - und ND 2 − -Ionen in Alkalihalogenidkristallen

The centers are produced by different methods. Either the crystal, containingF centers in a high concentration, is annealed in an atmosphere of ammonia. Or the NH ₄ ⁺ doped crystal is reduced withF centers. The optical absorption in the near infrared at 21 °K shows a well resolved doublett and another band at longer wavelengths. In the case of deuterated centers these bands are shifted by about √2 to longer wavelengths. These bands belong to the two stretching vibrations and the bending vibration of the NH ₂ ^? . In the UV a strong absorption band appears with satellites on its short wavelength side. Its maximum follows a Mollwo-Ivey relation. The satellites come from the simultaneous excitation of internal vibrations of the NH ₂ ^? . Their energy distance to the main maximum depends strongly on the hydrogen isotope. Excitation in the UV bands yields a flourescence in the visible region. It consists of two bands. They are interpreted as 0–0 transitions relative to the internal vibrations of the center. Their relative hight strongly depends on the temperature. We think that both bands are due to different positions of the amide ion in the excited state within the anion vacancy. From a detailed study of this temperature dependance typical activation energies can be derived.     

Bestimmung der optischen Konstanten von Lithium und Natrium durch optisch angeregte Oberflächenplasmaschwingungen

The ATR method to excite surface plasmons by light is used to measure optical constants of Lithium and Natrium in the energy region 2–3.8 eV. For energies smaller than 3.5 eV the real part of the dielectric function can be described by the equations valid for the free electron gas. The imaginary part shows an interband transition (~ 2.5 eV at Li, ~ 2.0 eV at Na), which is rather slow (about 1 eV) indicating an indirect transition.