First principles NMR study of fluorapatite under pressure
Barbara Pavan1, Davide Ceresoli, Mary M J Tecklenburg
1Science of Advanced Materials, Central Michigan University, Mt. Pleasant, MI 48859, USA. pavan1b@cmich.edu
Solid State Nuclear Magnetic Resonance
|July 10, 2012
Summary
Density functional theory (DFT) calculations reveal Nuclear Magnetic Resonance (NMR) parameters for fluorapatite under pressure. NMR accurately detects microscopic structural changes, aiding material science and biomedical applications.
Area of Science:
- Solid-state chemistry
- Computational materials science
- Mineral physics
Background:
- Nuclear Magnetic Resonance (NMR) is crucial for probing local material properties.
- Fluorapatite (FAp) is a calcium orthophosphate mineral with significant solid-state and biomedical applications.
- Apatite structures are open and susceptible to anisotropic deformation under pressure.
Purpose of the Study:
- To compute NMR parameters for fluorapatite using ab initio DFT calculations.
- To investigate the effects of hydrostatic pressure on FAp's structure and NMR response.
- To establish the sensitivity of NMR to pressure-induced microscopic changes in FAp.
Main Methods:
- Ab initio density functional theory (DFT) calculations.
- GIPAW (Gauge-Including Projected Augmented Wave) method for NMR parameter computation.
- Simulation of fluorapatite under hydrostatic pressure ranging from -5 to +100 kbar.
Main Results:
- Computed NMR parameters show good agreement with experimental data.
- Hydrostatic pressure causes shrinkage of the apatitic channel diameter.
- A strong correlation between NMR shielding and applied pressure was observed, demonstrating NMR's sensitivity.
Conclusions:
- DFT calculations provide valuable insights into fluorapatite's response to pressure.
- NMR is a sensitive technique for detecting subtle chemical environment changes in materials.
- This theoretical approach aids in interpreting experimental NMR data, especially for challenging nuclei like 43Ca and 17O.
