Investigating the role of carbon doping on the structural and energetic properties of small aluminum clusters using quantum Monte Carlo.

In this study, we investigate the energetics of small aluminum clusters doped with a carbon atom using several computational methods, including diffusion quantum Monte Carlo, Hartree-Fock (HF), and density functional theory. We calculate the lowest energy structure, total ground-state energy, electron population distribution, binding energy, and dissociation energy as a function of the cluster size of the carbon-doped aluminum clusters compared with the undoped ones. The obtained results show that carbon doping enhances the stability of the clusters mainly due to the electrostatic and exchange interactions from the HF contribution gain. The calculations also indicate that the dissociation energy required to remove the doped carbon atom is much larger than that required to remove an aluminum atom from the doped clusters. In general, our results are consistent with available theoretical and experimental data.