A Raman spectroscopic study of the plastically crystalline state of organic compounds

The depolarized and polarized components of internal Raman bands of succinonitrile, $\text{t}$-butyl chloride and $\text{t}$-butyl bromide in their plastic crystalline and liquid phases have been analyzed to obtain rotational and vibrational correlation functions. The rotational correlation times are continuous through the plastic-liquid transition and show an Arrhenius behaviour, from which activation energies for rotation have been calculated. Vibrational correlation times are nearly constant in the range of temperature investigated, except for a small change near the plastic-liquid phase transition temperature.