Raman polarization study of the film orientation of liquid crystalline NiPc

In this work, we determine, using Raman spectroscopy, the orientation of mo lecules relative to the substrate surface in films of octa(13,17-dioxanonac osane-15-sulfanyl)-substituted nickel(II) phthalocyanine, showing a liquid crystalline phase at room temperature. It was stated that the phthalocyanin e molecules in the film are disordered relative to the z-axis and rotated a round x and Y-axis on fixed alpha and beta angles, respectively. We study t he dependence of film orientation on temperature in the range from 0 to 30 degreesC. The alpha angle is decreased from 30 to 10 degrees with increasin g temperature, whereas, the beta angle is held constant (65 degrees). The p hase transition from liquid crystalline to isotropic phase in the NiPc film is observed at approximately 10 degreesC. (C) 2001 Elsevier Science B.V. A ll rights reserved.