Submillimetre wave spectroscopy of 4-n-alkyl-4′-cyano biphenyl liquid crystals

The absorption coefficient of the 4-n-alkyl-4′-cyano biphenyls has been studied in the submillimetre wave range 50-220 cm −1 . Molecular processes which give rise to superimposed but distinct absorption bands are reported. These processes have been analysed using a multi-oscillator model for the observed absorption and are assigned to the Poley absorption as well as to intermolecular and intramolecular mechanisms. Spectra at temperatures in the range 20-70°C and of solutions in cyclohexane support the proposed assignments.