Multiple dielectric relaxations in liquid crystals, their analysis and interpretation

Autor:	C. Stützer, Horst Kresse, Wolfgang Weissflog, S. Tschierske, A. Hohmuth
Rok vydání:	1996
Předmět:	Bond dipole moment Materials science Relaxation (NMR) Transition dipole moment General Chemistry Dielectric Low frequency Condensed Matter Physics Molecular physics Dipole Nuclear magnetic resonance Liquid crystal General Materials Science Absorption (chemistry)
Zdroj:	Liquid Crystals. 20:715-720
ISSN:	1366-5855 0267-8292
DOI:	10.1080/02678299608033164
Popis:	Dielectric measurements on laterally substituted molecules were carried out in the frequency range 10 Hz to 10 MHz. In these systems, the main part of the molecules exhibits only a very small dipole moment in the direction of the para-axis, whereas the lateral substituent is strongly polar. Depending on the position of the dipole (o,m,p), a more or less strong dipolar correlation in the parallel direction was detected. The absorption data at higher frequencies were fitted to two Cole-Cole mechanisms. The low frequency relaxation was interpreted as angular vibration of the dipole moment of the lateral group, and the high frequency one as the reorientation about the para-axis of the main part of the molecule and of the lateral group. The appearance of two high frequency mechanisms is unexpected and demonstrates that in complicated molecules the dynamics also become differentiated.
Databáze:	OpenAIRE
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