Vibrational modes of α-berlinite (AlPO4)

Abstract
We present a theoretical investigation of the lattice dynamics of α-aluminium phosphate (berlinite) which takes only into account short-range interactions and axially symmetric tensor forces between (i) the first nearest-neighbours metal-oxygen or oxygen-oxygen pairs and (ii) the second nearest-neighbours metal-metal pairs. Our calculation accounts satisfactorily for the experimental phonon frequencies deduced from infrared and Raman data and for the corresponding absorption strength of Raman scattering intensities.