Observation and identification of the molecular triplet in C-60 thin films

The excited state properties Of C-60 thin films have been probed at 77 K us ing Raman spectroscopy. The change in the Raman, A(2g) mode of C-60, whose position is largely independent of temperature was monitored as a function of the excitation intensity at 514.5 nm. This mode, normally positioned at 1469 cm(-1), was seen to shift to a lower Raman frequency with increasing l aser intensity, Two excited state species have been identified. The first, at 1466 cm(-1), has been associated with the molecular triplet of C-60, whi le the second species, at 1463 cm(-1), has been speculated to be an excited state co-operative in the solid. (C) 2001 Elsevier Science B.V. All rights reserved.