  Plane-wave pseudopotential methods and density functional perturbation theory
are used to calculate the phonon density of states and thermodynamic functions
of h-P4O10. The calculated vibrational spectrum is in good agreement with the
measured spectrum, but the calculations indicate some modifications in the
interpretation of the spectrum, mainly suggesting changes in the number of
components used to fit a few of the observed peaks. The calculated
low-temperature heat capacity is in good agreement with the measured heat
capacity, with a systematic offset of approximately -5 J mol-1 K-1, independent
of temperature. . Comparison with molecular calculations indicate that
molecular contributions make up about 80% of the heat capacity of h-P4O10
