GROWTH OF CARBON CLUSTERS - THE SIMPLEST PROCESS, 2C-1-]C-2, OBSERVED VIA SPECTROMETRY AND CHEMICAL-REACTION

A graphite sample has been irradiated with a YAG laser under an argon atmosphere. The emission due to the C2(d 3PI(g) --> a 3PI(u)) Swan band was observed with a decay time 20 times the intrinsic lifetime of C2(d 3PI(g)). In the presence of benzene, which reacts with C1, the observed decay time of the C2 Swan band decreased with increasing benzene around the graphite. Furthermore, the reaction products between benzene and C1 or C2 were identified and their distribution varied remarkably with benzene concentration. From these results, the simplest growth process of carbon clusters, 2C1 --> C2, was confirmed experimentally. Comparing the emission spectra from the irradiated graphite surface under an argon atmosphere and under vacuum, the collisional relaxation of C1 with argon was found to be indispensable to the growth process.