The absorption cross sections of C-60 and C-70 in the visible-UV region

Absorption cross sections of gas phase C-60 and C-70 in the 40000 to 16 000 cm(-1) region have been determined. The results are based on the combination of absorbance measurements of fullerene vapour, produced by the sublimation of samples in quartz double cells, and the vapour pressure measurements of the literature for solvent-free solid fullerenes. The gas phase cross sections are compared to those derived from molar extinction coefficients of C-60 and C-70 in hexene solutions and highlight the problems associated with the evaporation of solvent-containing fullerenes.