|
Title
|
|
|
|
ENDOR study of an O- ion observed in X-ray-irradiated carbonated hydroxyapatite powders
| |
|
Author
|
|
|
|
| |
|
Abstract
|
|
|
|
| A carbonated hydroxyapatite powder synthesized at high temperatures has been examined with electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR). In the EPR spectra, an intense signal assigned to an O- radical was observed. The interactions of the O- radical with three inequivalent sets of P-31 nuclei as well as with one set of protons were resolved in the ENDOR powder spectra. By a careful analysis of the ENDOR powder spectra using computer simulations based on the ''orientation-selection principle,'' a detailed model for the O- radical and its surroundings could be derived. In this way, it was established unambiguously that the O- ion is located on a hydroxyl site. In addition, experimental evidence was found that the precursor of the O- radical is a carbonate group, and not a hydroxyl group. Next to the O- radical, EPR and ENDOR resonances of another paramagnetic center were observed. After analysis of the spectra and by comparing the results with previous work, this radical was assigned to a CO33- ion located at a phosphate site. |
| |
|
Language
|
|
|
|
English
| |
|
Source (journal)
|
|
|
|
Physical review : B : condensed matter. - New York, N.Y., 1978 - 1997
| |
|
Publication
|
|
|
|
New York, N.Y.
:
1996
| |
|
ISSN
|
|
|
|
0163-1829
[print]
1095-3795
[online]
| |
|
DOI
|
|
|
|
10.1103/PHYSREVB.53.5190
| |
|
Volume/pages
|
|
|
|
53
:9
(1996)
, p. 5190-5197
| |
|
ISI
|
|
|
|
A1996UA01100039
| |
|
Full text (Publisher's DOI)
|
|
|
|
| |
|