Spectral and quantum-mechanical study of electronic structure of ultradispersed calcium hydroxyapatite
The regularities of electronic structure of calcium hydroxyapatite samples of different genealogy were investigated by X-ray, IR spectroscopy methods and by quantum-mechanical calculations - Xa and LMTO (methods of the band theory). The evolution of valence band and charge states of atoms is describ...
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| Date: | 2002 |
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| Main Authors: | , , , |
| Format: | Article |
| Language: | English |
| Published: |
Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine
2002
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| Online Access: | https://surfacezbir.com.ua/index.php/surface/article/view/83 |
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| Journal Title: | Surface |
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Surface| Summary: | The regularities of electronic structure of calcium hydroxyapatite samples of different genealogy were investigated by X-ray, IR spectroscopy methods and by quantum-mechanical calculations - Xa and LMTO (methods of the band theory). The evolution of valence band and charge states of atoms is described. It was established that distribution of p- and d‑electronic states of calcium in samples of calcium hydroxyapatite of different origin is practically identical. Beside a high ionic component, covalent and hydrogen bonds are present in calcium hydroxyapatite. The indirect metal-metal interaction is observed in a metal sublattice. It was shown that a sublattice of the phosphatic tetrahedra determines the shape and main features of a valence band of calcium hydroxyapatite. The lack of a part of calcium ions in the nonstoichiometric samples results in weakening of P-O bond within a mirror plane. An influence of the crystal-ultradispersed state transition on the shaping of X-ray emission spectra was first investigated. Considerable localisation of metal d-states is observed in the ultradispersed hydroxyapatite samples. |
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