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Abstract
An idea for a method of experimental determination of tilt angles and order parameters of cylindrosymmetric transition moments of liquid crystals and of dyes in host-guest systems is described. Furthermore, first experimental hints are given. With freely rotating molecules, all transition moments result in an isotropic absorbance for UV/VIS-spectroscopy using polarized light. The resulting absorbance becomes anisotropic if the transition moment of the molecules is polarized, the molecules are aligned in a preferential direction, and the free rotation is suppressed. In this case, the measurement of Aiso, Atilt, and Atilt using polarized light is sufficient to calculate the related tilt angle Psi, the order parameter S, and the absorbance A as a function of the polarization angle. The local electric field and its influence on the dichroic ratio of an absorption band has not been considered. The precision of this method is still limited by the photometric accuracy of the spectrometer and the mechanical precision of the goniometric adjustment of the experimental apparatus.
