Formation of carbon clusters C-n(1<=n<=4) by laser vaporization of graphite and a study of their chemical reactivity by gas chromatography-mass spectrometry

Experimental evidence for the formation of C-1, C-2, C-3 and C-4 carbon clusters by the laser vaporization of pure graphite in liquid and gaseous benzene environments has been obtained by using a gas chromatography (GC) coupled with mass spectrometry (MS) analysis system. A constant irradiance was chosen: 10(10) W cm(-2). In the gaseous benzene phase, one aggregation process of C-n was noticeably more important than in the liquid benzene phase. Two types of laser reactions may be distinguished: the addition of carbon clusters to a phenyl radical and the aggregation of carbon clusters resulting in carbyne compounds (CnH2). The effect of the wavelength of the focused laser beam is also discussed. There are shown to be contributions from two major kinds of interaction: a thermal interaction for IR and visible irradiation, evidenced by formation of C-2 clusters and photoelectronic effects from UV photons, evidenced by a high concentration of toluene.