Zusammenfassung
The phonon properties of the lithium transition metal phosphates LiMPO4 (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
LiNiPO4 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 LiCoPO4 Raman wavenumbers also
compared well with experimental values (average deviation 9%). Using
this procedure, the 36 Raman wavenumbers, of LiFePO4 were predicted and
assigned to vibrational motions and symmetry species of the crystal
group. LiFePO4 unpolarized Raman data agree very well with the predicted
values. Copyright (c) 2004 John Wiley & Sons, Ltd.
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