Polarized IR and Raman spectra of (H2O)n clusters (n = 2–5) in the c-channels of apatite single crystals

Abstract

The infrared (IR) and Raman spectra of three samples of fluorapatite single crystals and carbonate fluorapatite single crystal in the region of 7000–400 cm^–1 were studied. It has been shown that isomorphic substitution of the Ca²⁺ cation and the PO₄^3- anion leads to an increase in the size of the c-channels in the apatite crystal, which is accompanied by the formation of water clusters of the (H₂O)_n and H₃O⁺ · (H₂O)_n (n = 2–5) types as a result of the diffusion processes in these local sections of the c-channels.