Accordingly, indirect approaches have been extensively used: One is microstructural analysis of the obtained PP, using C NMR for example, to gather information on the active sites. The other is the use of ab initio methods to calculate adsorption energies and plausible structures. In particular, density functional theory (DFT) calculations have been a popular method for more than 20 years, and have provided valuable insights into the system. However, until now, these calculations have been mostly limited to infinite slab surfaces or ideal nanoclusters with well-defined terraces and high symmetry, that did not account for the adsorbate-induced reconstruction. These simulations start with defined support structures and investigate the adsorption thereon, thus they cannot model the dependence of the structure on the adsorption, as the latter is being defined by the former.