Quantum nature of stability mechanisms of calcium apatite structure

Abstract

The role of the nascent d-shell of calcium in the formation of the anoma- lous features of calcium apatite depending on the composition, synthesis conditions, changes in dimensionality and topology of key elements is in- vestigated. A detailed analysis of the electronic structure of calcium apa- tite is performed with spectral and theoretical methods. The limitations of the application of quantum-mechanical calculations using the methods of the density functional theory to the description of the long-range compo- nent of the interaction of calcium with the surroundings are established. In turn, experimental data indicate that the stability of the structure of apatite is determined largely by the two-valley effective potential of calci- um d-electrons. In various calcium compounds, atomic effects play a sig- nificant role in forming the shape of the L-spectra of calcium, and, as a result, the participation of d-states of calcium in bond formation is lev- elled by their significant localization, apparently, in the inner valley of the effective potential.