Growth of carbon clusters. The simplest process, 2C1→ C2, observed via spectrometry and chemical reaction

Abstract

A graphite sample has been irradiated with a YAG laser under an argon atmosphere. The emission due to the C₂(d ³Π_g→ a ³Π_u) Swan band was observed with a decay time 20 times the intrinsic lifetime of C₂(d ³Π_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.