Shell-model study of the lattice dynamics of hydroxyapatite
Bibliographic record
Abstract
A shell model has been developed and used in a study of the lattice dynamics of hydroxyapatite. The results give insight into the modes of vibration of the lattice, but in addition, the dynamics has been used to obtain quantities involved in x-ray and neutron diffraction patterns and in infrared spectra to help in the interpretation of experimerimental data. Phonons throughout the Brillouin zone were obtained and used to calculate atomic thermal factors entering the x-ray and neutron scattering intensity. The calculated values were in very good agreement with experiment. The phonon modes were also obtained for the $\ensuremath{\Gamma}$-point taking into account the long range Coulomb correction to the dynamical matrix. They were used to calculate the infrared reflectivity for single crystals of hydroxyapatite through the dielectric function and using the dipole approximation, and the powder spectrum was also obtained using the dipole method. Although the positions of peaks in the measured intensities were in good agreement with the frequencies of features in the calculated phonon density of states, the calculated intensities were in poorer agreement with experiment.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".