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Measurements of the Rayleigh-Brillouin spectra of the binary system nitroethane-isooctane have been carried out as function of temperature and concentration. The purpose of this investigation was to study the transition of one type of phase transformation to an other. Taking the temperature as variable, the phase transformation is of second order for one specific concentration – the critical concentration, whereas for other concentrations it is of first order. Samples deviating up to 20% from the critical composition have been investigated in the temperature range 10 to 10−3 K above the transition temperature in the homogeneous region. The temperature dependence of the Rayleigh-Brillouin intensity ratio Ir/2Ib can be described by the same critical exponent γ = 1.24 for all concentrations provided the critical temperature in the scaling function is replaced by another reference temperature, interpreted as pseudo-spinodal temperature T*s The concentration dependence of T*s is found to be |X – Xc| = A · Tβ*s, where ts is the reduced temperature ts = 1 –T*s/Tc. The value of the exponent is found to be β* = 0.5, which is the classical exponent of the spinodal curve.

The influence of an external magnetic field on the normal incidence reflectivity of CuCl single crystals has been measured in the Voigt and Faraday configurations. The results are discussed in terms of the dielectric function calculated from the reflectivity spectrum by a Kramers-Kronig transformation. In the Voigt configuration two new exciton bands can be observed, which are attributed to a triplet and a longitudinal exciton. Their energetic positions are used to determine the parameters of electron-hole exchange interaction in the 1s excitons, and the spin-orbit splitting parameter of the upper valence band. The excitonic g-values are determined from the Faraday configuration measurements and can be interpreted on the basis of the tight binding model.

The magnetic circular dichroism of the K-band in the alkali halides RbCl, RbBr, RbI, KCl, KBr, and KI has been measured at temperatures between 4.2 and 77 °K. The magnetic field up to 50 kG was produced by a superconducting solenoid. We interpret the experimental results using the method of moments. The spin-orbit splitting and the orbital g-factors of the excited states due to the K-band are determined. Furthermore we obtain matrix elements describing the mixture of the excited states giving rise to F-and K-bands. In accordance with calculations of Smith [15] the measurements confirm the Mott-Gurney model, which attributes the K-band mainly to 1s-3p transitions. Der magnetische zirkulare Dichroismus der K-Bande wurde in den Alkalihalogeniden RbCl, RbBr, RbJ, KCl, KBr und KJ bei Temperaturen von 4.2 bis 77 °K gemessen. Als Magnet diente eine Supraleitungsspule, mit der Magnetfelder bis zu 50 kG erzeugt werden konnen. Die Auswertung der Messungen geschieht nach der Methode der Momente. Man erhalt Spin-Bahn-Aufspaltungen und orbitale g-Faktoren der angeregten Zustande des K-Uberganges. Auserdem werden Matrixelemente bestimmt, die die Mischung der angeregten Zustande des K- und F-Uberganges beschreiben. In Ubereinstimmung mit Rechnungen von Smith [15] bestatigen die Messungen das Mott-Gurney-Modell, das die K-Bande im wesentlichen 1s-3p-Ubergangen zuordnet.