Formation of bicyclic polycyclic aromatic hydrocarbons (PAHs) from the reaction of a phenyl radical with -3-penten-1-yne.

The formation of polycyclic aromatic hydrocarbons (PAHs) on the CH potential energy surface involved in the reactions of a phenyl radical (CH) with -3-penten-1-yne (-CH[triple bond, length as m-dash]C-CH[double bond, length as m-dash]CH-CH, referred to as CH) and its three radicals (CH[triple bond, length as m-dash]C-Ċ[double bond, length as m-dash]CH-CH, CH[triple bond, length as m-dash]C-CH[double bond, length as m-dash]Ċ-CH, and -CH[triple bond, length as m-dash]C-CH[double bond, length as m-dash]CH-ĊH, referred to as the C-, C-, and C-radicals with the same chemical components, CH) assisted by H atoms is investigated by performing combined density functional theory (DFT) and calculations. Five potential pathways for the formation of PAHs have been explored in detail: Pathways I-II correspond to the reaction of CH with CH at the C and C position, and Pathways III-V involve the reaction of CH with the C-, C-, and C-radicals with the assistance of H atoms. The initial association of CH with CH or CH is found to be highly exothermic with only minor barriers (1.