Optical and thermodynamic properties of isolated fullerene molecules

Measurements of the optical absorption spectra of gas phase C-60 and C-70 molecules, generated in a heat-pipe oven, from 200 nm to 400 nm, are reported. Four peaks at 378 nm, 332 nm, 232 nm and 208 nm for isolated C-70 and three absorption peaks at 328 nm, 254 nm and 207 nm for isolated C-60 and the corresponding absorption cross sections for the molecules were determined separately. In addition, the dependence of molecular absorption on the temperature was also obtained, and thus the temperature dependence of the fullerene vapour pressure and the heat of sublimation, as well as the decomposition temperature of the fullerene molecular cage structure, were estimated.