LASER PHOTOLYSIS OF LIQUID BENZENE AND TOLUENE - GRAPHITIC AND POLYMERIC CARBON FORMATION AT AMBIENT-TEMPERATURE

ArF laser photolysis of liquid benzene and toluene yields hydrogen, me thane, ethene, ethyne, aromatic hydrocarbons and carbon. The preponder ance of biphenyl among the aromatic products from photolysis of benzen e, and that of bibenzyl among those from photolysis of toluene reveals the importance of the phenyl and benzyl radical combinations in the i nitial stages of photolysis. XPS and Raman spectroscopies showed the c arbon to contain both sp(3) and sp(2) components and to consist of gra phitic and polymeric constituents. The remarkable feature is that the carbon formation occurs at ambient temperature of the irradiated liqui ds; photolytic graphitization modes must therefore be different from t hose involved in thermally-induced graphitization which takes place at temperatures above 2500 degrees C. (C) 1997 Elsevier Science Ltd.