The role of oxygenated species in the growth of graphene, fullerenes and carbonaceous particles

On the Mechanism of Soot Nucleation. IV. Molecular Growth of the Flattened E-Bridge

“…Considering the similarity in the underlying mechanism of the flip transformation, we assumed that the seven-membered-ring flip reactions occur with rates similar to those of five-membered rings. The latter were computed , to be on the order of 10 9 –10 10 s –1 , i.e., occurring much faster than other aromatic edge processes, and therefore could be modeled by partial equilibrium. , The same was assumed for the flip reactions of the seven-membered rings in the present kMC simulations.…”

“…A theoretical study of Whitesides et al 39 suggested that fivemembered rings embedded at the graphene edges can undergo rapid H-activated migration along a zigzag edge, as illustrated in the top panel of Figure 5. Tested in kMC simulations, 37,40 this type of migration was indeed shown to be a frequent event. More recently, 32 the same mechanism of the fivemembered ring migration was shown to be one of the dominant events in the structural evolution of PAHs, exhibiting interconversion among embedded, partially embedded, and zigzag-edge five-membered rings.…”

“…The latter were computed 39,41 to be on the order of 10 9 −10 10 s −1 , i.e., occurring much faster than other aromatic edge processes, and therefore could be modeled by partial equilibrium. 37,40 The same was assumed for the flip reactions of the seven-membered rings in the present kMC simulations. The computed statistics for the flip reactions of sevenmembered ring are shown in Figure 8.…”

Stochastic population balance methods for detailed modelling of flame-made aerosol particles

“…A similar statistical modelling framework is also widely employed to study collisions between gas molecules in 'kinetic Monte Carlo' (kMC) simulations (Violi et al, 2005). Here too, the Monte Carlo approach can accommodate detailed descriptions of the compositions of collision partners, for example enabling description of curvature in PAH molecules by tracking both six-and partially-embedded, five-member rings (Leon et al, 2021). DSMC is also applied to solve the Boltzmann equation in the study of gas diffusion in porous media (Dreyer et al, 2014) and diffusion with reaction in heterogeneous catalysis (Pesch et al, 2015), where it enables chemical kinetics to be incorporated into reactor-scale models for comparison of both micro-and macroscopic observables (Swapnasrita et al, 2021).…”