Chapter 2 - Energy landscapes and dynamics of polycyclic aromatic hydrocarbon clusters from coarse-grained models

Abstract

Polycyclic aromatic hydrocarbons (PAHs) have received growing attention owing to their importance in various fields, such as combustion and astrochemistry. Clusters of PAHs are prototypes of complex molecular assemblies only bound by noncovalent forces, but with extremely anisotropic building blocks. In this chapter, their computational modelling is discussed in the light of coarse-grained approaches in which the individual molecules are treated as single-site ellipsoids interacting with each other through repulsion and dispersion forces, possibly with a quadrupolar electrostatic correction. Pure and mixed clusters of pyrene, coronene, and circumcoronene generally exhibit columnar motifs and multiple funnel energy landscapes. Their finite-temperature behaviour and rearrangement pathways obtained with the coarse-grained models are compared with the predictions of all-atom descriptions. The approximate aggregation kinetics of a high-temperature molecular vapour is also modelled using a Monte Carlo scheme.