FT-Raman-spectroscopic study on the luminescence of synthetic and mineral apatites

Strong luminescence bands can be present in NIR-excited FT-Raman spectra of certain inorganic materials like hydroxyapatite. Since the origin of these emissions exclusively occurring on NIR-excitation is still unclear, a variety of synthetic and mineral apatites and related calcium salts was studied by means of Stokes and anti-Stokes FT-Raman spectroscopy, X-ray diffraction, and geochemical analyses. The results indicate that the occurrence of the luminescence is in some way related to foreign ion contents. However, a direct correlation to a specific ion could not be found on the basis of available data.