Theoretically, many possible mechanisms have been proposed for the formation of PAH and soot inception. As for PAH growth, the hydrogen abstraction-acetylene addition (HACA) mechanism was proposed by Frenklach et al . The phenyl addition-cyclization (PAC) is another mechanism that provides an efficient way for ring growth . The recently proposed clustering of hydrocarbons by radical-chain reaction (CHRCR) mechanism also provides a possible route for the PAH growth . Additionally, when the density of fuel is high, the polymerization reactions may also be an alternative mechanism . Compared with the PAH growth, the formation of soot inception is much more complicated. The number of reaction pathways involved in forming larger molecules grows exponentially with their sizes. Traditional quantum chemical calculation methods such as the transition state theory can only study several specified reactions at a time, thus it is difficult to efficiently study such a complex system. In the past decades, molecular dynamic (MD) simulation with reactive force field as well as ab initio MD simulations (AIMD) have gradually become a main tool for the study of PAH growth and soot nucleation. AIMD is undoubtedly more rigorous and accurate. However, long-time AIMD simulation for systems that contain thousands of atoms is currently not practical due to the computational cost. On the other hand, although MD simulation using reactive force fields such as ReaxFF are computationally tractable for such large systems, their accuracy is often questionable with respect to higher-level quantum mechanical approaches (e.g., ab initio density-functional theory) and remains to be fully experimentally validated.