Phonon calculation on olivine-like LiMPO4 (M = Ni, Co, Fe) and Raman scattering of the iron-containing compound
✍ Scribed by W. Paraguassu; P. T. C. Freire; V. Lemos; S. M. Lala; L. A. Montoro; J. M. Rosolen
- Book ID
- 102422544
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 330 KB
- Volume
- 36
- Category
- Article
- ISSN
- 0377-0486
- DOI
- 10.1002/jrs.1278
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✦ Synopsis
The phonon properties of the lithium transition metal phosphates LiMPO 4 (M = Ni, Co, Fe) with the olivine structure were studied using a computational simulation. The calculation employs a normal coordinate analysis based on the Wilson's FG matrix method. The method applied to LiNiPO 4 allowed for the fitting of a set of stretching force constants and angle bond strengths that resulted in Raman wavenumbers comparing with experiments within a 5% average deviation. This set was assumed fixed for the isostructural Co-containing and Fe-containing compounds, as a first approximation. The calculated LiCoPO 4 Raman wavenumbers also compared well with experimental values (average deviation 9%). Using this procedure, the 36 Raman wavenumbers of LiFePO 4 were predicted and assigned to vibrational motions and symmetry species of the crystal group. LiFePO 4 unpolarized Raman data agree very well with the predicted values.