HPLC analysis for fullerenes up to C90 and the use of the laser furnace technique to study fullerene formation process

The ambient temperature dependence of the yield of fullerenes was systematically investigated toward furthering the understanding of the fullerene formation mechanism. The change in yield of fullerenes from C-60 to C-96 was quantitatively examined as a function of fullerene size, temperature, and position of target in the gradient of temperature. As a result, it was found that the formation of higher fullerenes requires higher furnace temperature, presumably because of the presence of higher reaction barriers prior to the accomplishment of the fullerene cage. In connection with such a thermal effect on the yield of fullerenes, we have also carried out an experiment to deduce the spatial distribution of such an endothermic reaction area in which the external heating is effectively active. Furthermore, in order to establish the presence of such a particular area for the fullerene formation, we used a high-speed video camera to directly detect emission from hot particles, which was found to be closely related to fullerene formation.