| Abstract
| - The phosphorescence spectrum of C60, recently obtained in alkane and in Xe matrixes at low temperature,has been modeled by means of semiempirical quantum chemical calculations. The T1 → S0 transition in theunperturbed molecule is symmetry as well as spin multiplicity forbidden. The intensities of the false originsdue to inducing modes have been calculated in terms of the Herzberg−Teller mechanism combined with anexpansion over spin−orbit perturbations. To date, this is the first modeling of the phosphorescence spectrumof C60 entirely based on computed molecular parameters. Thus, the analysis of the spectrum is based not onlyon vibrational frequencies, but also on the comparison between computed and observed vibronic intensities.The calculations indicate that the vibrational structure is dominated by false origins due to modes of hu, gu,and t1u symmetry, but contains also a number of combination bands based mainly on the Jahn−Teller activehg(1) mode.
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