Modelling hydroxyapatite by periodic DFT calculations : from bulk properties to surface adsorption processes

This talk will give a survey of the atomic-scale modelling of hydroxyapatite (HA) obtained by means of periodic calculations carried out using density functional theory (DFT) and adopting linear combination of atom-centered Gaussian-type orbitals (GTO) as basis sets. In the first part, the effects on the calculated bulk structural parameters related to the choice of functionals, the inclusion of the corrections for dispersive forces, and the use of different basis sets will be presented. The differences between the data computed with the adoption of all-electron basis sets for the Ca ions and the ones yielded by calculations carried out with an effective core pseudopotential basis sets will be considered. The results obtained for the structural parameters and some relevant mechanical properties will be presented and compared with respect to the experimental data. In the second part of the talk, the main steps for the modelling of the adsorption process on different relevant HA surfaces will be introduced, and a brief survey of some recent results will be presented.