In Search of the Molecular Triplet of C_(60) using Low Temperature Raman Spectroscopy

摘要

The excited state properties of C_(60) thin films have been probed in the temperature range 77-273K using Raman Spectroscopy. The change in the Raman, 2A_g mode of C_(60) (whose position is largely independent of temperature) was monitored as a function of the excitation intensity at 514.5nm. This mode normally positioned at 1469cm~(-1), was seen to shift reversibly to a lower Raman frequency with increasing laser intensity, Two excited state species have been identified. The first, at 1466cm~(-1) has been associated with the molecular triplet of C_(60). The second species at 1463cm~(-1), has been speculated to be an excited state co-operative involving two or more excited states in the solid and is seen to be intrinsic to solid state C_(60) below the phase transition.