| Abstract
| - A better understanding of the formation of polycyclic aromatic hydrocarbons (PAH) is of great practicalinterest because of their potential hazardous health effects and their role as intermediates in soot and fullereneformation. The potential surfaces of the reactions C6H5 + C2H2 and 1-C10H7 + C2H2 were explored by density-functional theory using BLYP and B3LYP functionals. Vibrational analysis allowed the determination ofthermodynamic data and deduction of high-pressure-limit rate constants via transition state theory. The pressureand temperature dependences of these chemically activated reactions were computed using the modified strongcollision approximation. The comparison of the predictions for the C6H5 + C2H2 system with experimentaldata showed good agreement in particular at high temperatures relevant for a combustion environment. Thedominant product from acetylene addition to 1-naphthyl at low pressures is the five-membered ring speciesacenaphthylene, consistent with the more pronounced formation of fullerenes under such conditions. Highpressure favors formation of stabilized initial adducts, i.e., phenylvinyl and 1-naphthylvinyl. Some productsnot considered previously, such as 1-acenaphthenyl, 1-naphthylacetylene, 2-vinylphenyl, and 1-vinyl-2-phenyl,are found to be important under some pressure and temperature conditions. All of our results are consistentwith known free-radical chemistry. Rate constants describing the formation of phenylacetylene, phenylvinyl,1-vinyl-2-phenyl, 1-naphthylvinyl, 1-vinyl-8-naphthyl, 1-naphthylacetylene, acenaphthylene, and 1-acenaphthenyl are given at 20 and 40 Torr as well as at 1 and 10 atm for the temperature range from 300 to 2100 K.
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