Revisiting hollow all-carbon structures: Aromaticity and kinetic stability

In this work, the aromaticity of the so-called hollow carbon structures, previously proposed as an novel allotrope of carbon, has been revisited through the bifurcation values of the electron localization function (ELF) as a complement to the previous results obtained through the magnetic criterion for Gaudiene (C₇₂). Additionally, we studied systems with 162, 216, and 648 carbon atoms were studied. Since, in large systems, the use of methodologies such as DFT can often be prohibitive, the GFN2-xTB method has been applied, whose wavefunction has been used to calculate the ELF. To the authors' knowledge, this is the first time an ELF study has been carried out with large systems and this method. On the other hand, the kinetic stability has been evaluated using molecular dynamics simulations at different temperatures. The results show that the hollow carbon structures present aromatic character, leading to high thermodynamic and kinetic stability, making them good candidates for exploring diverse and interesting applications. Finally, it is demonstrated that GFN2-xTB imethod allows the successful study of large systems where the analysis using DFT or post-Hartree-Fock calculations would have a high computational cost.