No abstract

The Raman spectra of the CT‐crystal anthracene‐TCNB are investigated in the temperature range between 10 and 300 K. The orientational phase transition of the crystal at 206 K is observed from the temperature dependence of the resonance frequencies, intensities, and linewidths. It is shown that the low‐temperature structure is ordered and that a superstructure is formed. An assignment of some modes on the basis of isotropic shift and preresonance enhancement data is presented. Especially the frequencies of those anthracene librations are given, that are involved in the phase transition. The most intense line in the spectrum is attributed to a translational motion along the normal coordinate nearly parallel to the stack axis.