A theoretical study of the potential energy surface for the isomerization reaction of fluoranthene to aceanthrylene: Implications for combustion chemistry

Isomerization reaction of fluoranthene forming aceanthrylene was investigated using density functional theory (DFT). Geometrical structures and scaled vibrational frequencies all species thermodynamic properties including standard enthalpies ΔrH°(T) Gibbs free energies ΔrG°(T) were calculated at a wide range temperature from 298 to 2500 K the B97D3/6-311++G(3df,2p)//B97D3/6-311++G(d,p) level theory. Consequently, isomerization is initiated via two pathways, either by hydrogen 1,2-shift or carbon reactions with barrier 356.6 393.6 kJ mol−1. Also, co-existence acephenanthrylene observed corresponding ΔrH°(0 K) 28.5 53.7 Kinetic calculations for initiative step confirm that in comparison mechanism always predominant. However, as shown kinetic calculations, these are not relevant under flame conditions. It may need find other pathways explaining conversion intermediate pyrene.