Pressure-induced orientational ordering in C60 crystals as revealed by Raman spectroscopy

Pressure-induced molecular orientational ordering in single crystals of C60 has been studied by Raman spectroscopy. The strongest intramolecular mode attributed to the double-bond stretching “pentagonal pinch” vibration shows considerable softening across the transition around 3.5 kbar. The linewidths also increase considerably at higher pressures, indicating an orientational glassy state.