The variation of vibration amplitudes with temperature in some molecular crystals

Abstract

The theory of the translational and rotational vibrations of molecules in molecular crystals is discussed. Characteristic lattice frequencies for translational and rotational vibrations, derived from X-ray and Raman studies, are used to predict the variation of the molecular vibration amplitudes with temperature in benzene, naphthalene and anthracene. There will be little gain in using temperatures below about 25 � K. for studies of the fine details of the electron density of these molecules.