Characterization of the Minimum Energy Paths for the Reactions of CH(X(sup 2 Pi) and (1)CH2 with C2H2

The reactions of CH(sup 2 Pi) and singlet methylene (1)CH2 with acetylene lead to intermediates which may be important in soot formation. CH(sup 2 Pi) + acetylene leads to CHCHCH (C3H3), CHCCH (C3H2), and propargyl (CH2CCH). (1)CH2 + acetylene leads to cyclopropene and propargyl. All of these reaction products are formed with no barrier. Miller and Melius have previously discussed the dimerization of propargyl to give benzene. C3H3 and C3H2 can dimerize with no barrier to give benzene and para-benzyne, respectively. C3H3 and C3H2 can also add to smaller polynuclear aromatic hydrocarbons (PAH), and may be important species in forming larger PAH or fullerenes.